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Multiple Threads Starting Up Spontaneously

I've got a very bizarre situation. It appears that, when I load a webpage to my browser,
multiple threads (at least 2) are starting up. The app loads and runs fine on a
Windows XP box, but when I try to run it on my Windows 8 laptop it would seem that
more than one startup event is taking place and causing all kinds of collisions. This
is happening with both Firefox and IE.
To verify this behaviour, I placed a static int within a class, checked it to see if its
value is greater than zero, throw an exception if it is, then increment the int.
Of course, the exception is thrown.
What's very weird about this is that there is no multi-threading/multi-tasking involved
within my app.
When I "touch" the DLL for the webpage (rebuild it), it renders the webpage properly,
but the source for the webpage ("right click" > "View Page Source") has the source
for the unhandled exception webpage, with the message for the exception that my code
throws when the thread count is greater than zero.
I've tried creating a new project, then linking the code to it (Add Item ... Ad As Link),
then building it. It didn't do any good.
The Win XP system has IIS 6 with .NET 4.0, and the Win 8 laptop has IIS 7 with .NET 4.0.
Language is C#.
The truth is that I'm pretty much clueless about IIS.
I hope someone smarter than I am (which isn't saying much) has an idea as to what
is going on.

It appears that, when I load a webpage to my browser, multiple threads (at least 2) are starting up
Maybe onetime initializations. I doubt that every request causes an additional two threads to stay around.
it would seem that more than one startup event is taking place
That's normal This event fires for each instance of HttpApplication being created. This is basically a design error in ASP.NET. They thought that pooling HttpApplication instances and assigning one of them for each request was a good idea. It would have been better to have a singleton per AppDomain. Write this yourself. Like that:
class MyGlobalAppState { ... }
static Lazy<MyGlobalAppState> state = new Lazy<...>(StateFactory);
Be aware, that Lazy<T> stores any exception and just rethrows it. This causes your app to be permanently broken in case StateFactory throws. It will never recover without pool restart. This is a design error in Lazy<T>. Find a way to deal with that.
but the source for the webpage ("right click" > "View Page Source") has the source for the unhandled exception webpage
Some browsers re-GET the page to view the source. This can be annoying or handy.

It is hard to tell what is causing this behavior but as others suggested try to use Fiddler or any other http tracing tool to see what requests are sent.
Also, Win XP should be running IIS5.x while Win8 should be running IIS8.
By default IIS8 AppPool should be running with the integrated pipeline, which may behave differently. I would try changing the AppPool to use the Classic pipeline to see if it makes a difference.

Why is Selenium + Firefox freezing while loading pages?

I'm running the latest version of Firefox and Selenium in C#. I'm automating a crawler to find data in a web app. The server is super slow, so I've had to add in many waits plus put in initial wait using thread sleep.
So my crawler gets a list of items, then iterates: it has to load the details of each item by clicking on its id. Then it goes back (these navigation controls are all built into the web app, no browser controls used), rinse and repeat. The server shows a progress spinner during loading details and going back. The crawler reaches the same item each time and locks, eg: the progress spinner freezes and Firefox crashes.
I've tried a couple of different things including using background threads, deleting all cookies, and checking if my memory is overloading. I haven't noticed any peaks in memory (in task manager). I also tried restarting web driver but it doesn't really work out well because this is a web app.
Is there something I'm overlooking? (I tried to be as clear and elaborate as possible)
Forgot to mention, when I stop the program the page 'unfreezes' and I can continue use from that point.

This was a known problem with C# selenium web bindings 2.39 and earlier. This should now be fixed in 2.40. The problem was to do with a deadlock in the web bindings code when redirecting console logging from firefox. If you upgrade to 2.40 it should solve it. See here under the heading 'Update 25th Feb 2014' for more information.

How to wait for the post back in Watin?

In my C# code, I am using Watin to navigate the web, to log in to a page, I need to click the log in button, but right after I want to log out, so I have the click log out button right after, but the log out part doesn't work. I even tried closing the browser (using the close method) after logging in, but it didn't work. It feels like as soon as the page gets changed (i.e. after logging in) no more commands from the c# will work.
Does anyone know whats wrong?

As mentioned in another answer Thread.Sleep(milliseconds) is a way to wait for a time period for something to load. Very, very easy to implement, but it is far from optimal due to varying load times, and if you make it long enough so that it will always wait long enough you'll end up with a lot of wasted time. On one test this is not a big deal, but for instance if you have to wait 5 seconds and you have 1000 tests.... etc etc etc.
The route I've gone is:
Put in Thread.Sleep()s to determine if it is a "wait" issue.
If the the code with the Sleep() is going to be used more than once figure out what is causing the need for the sleep().
Refactor out the Sleep() using various Wait...() methods. WaitTilExists, WaitForAttributeEqualsWhatever, WaitForAsyncToFinish <- Not real methods, but WatiN has a bunch built in
The big cause of waits for me now is JQuery asynchronous calls in ASP.NET and I made a static helper class that works well for me to wait for async calls to finish. These tend to be very specific to what framework(s) the sites you're testing are written in.

The watin click command wait until the browser is loaded so practically it wait for the postback.
In case if you using ClickNoWait() command it will not wait.
So if your code looks like this it should work:
browser.GoTo("www.your-site.com");
// fill user/pass
browser.Button(Find.ByClass("login-class")).Click();
browser.Button(Find.ByClass("logout-class")).Click();
In case it's still not working you can add this after login click browser.WaitForComplete();

In Watin you will encounter many situations where the code is non blocking (you'll execute a line of code and will immediately keep going) so for those cases you'll need to find a different way to know that the next page (action, etc.) is already there. For example, on a login page you could check if that pages has a TextBox called UserName:
<code>
TextField uName = browser.TextField(Find.ByName("userName"));
if(uName.Exists)
{
// Then do the login code....
}
</code>
In the same way you should control that the page after the login is there before you keep going executing your code. So for example, if you are logging in into a page that you know that will contain the text: "Your Account Details" you might do something like this:
<code>
browser.GoTo("http://www.yourdomain.com/login.aspx");
//do your login code
browser.WaitUntilContainsText("Your Account Details", 240); // the second parameter indicates the seconds it will wait before it times out.
// your code to deal with the page after the login.
</code>
Using Thread.Sleep is a recipe for confusion and that's a problem for sure, you will NEVER get the timing right with a web page (even if you think it will take 10 seconds it might never come back and at that point the server will be terminating the opened connection).
Hope it helps.

Use Thread.sleep in your scripts to sync with logout and login...
or
instead of logout you directly close application and use ie instance to relogin to application

C#, WebBrowser, how to inject and execute JavaScript before any other script on the page?

I know how to inject my own scripts into web pages on load event, but it doesn't always work as expected. Sometimes the page succeeds to run its own scripts before mine and it makes my whole app fail. I try do disable the possibility the page spawns another browser window. I have an app running on my server, when it starts Internet Explorer instances randomly - it soon crashes the whole machine which is a disaster.
I made a script which changes window.open method and it does the trick perfectly - except the case when the page pops up another window BEFORE my code is executed. Is there a way to freeze JS before I finish injecting my script? Maybe is there a way to inject my script in an earlier point, before DocumentCompleted event? But how?

This doesn't directly answer your question about how to do it in the browser - but I'm aware of a similar thing that is done by Avast internet security and it does it using an HTTP proxy.
The idea is to intercept HTML pages as they are received over the wire, and inject your script into the HTML itself; thus there's no way that any other script can execute before it.
Whilst that might sound scary - you can do it using the technology underpinning the very excellent Fiddler HTTP debugger - the FiddlerCore API

Silverlight/WP7 - Navigation and events triggering on other pages

My basic issue is this, I have events firing on pages I've left based on network activity that are causing problems when I thought the old forms were being destroyed.
More detailed information: I am writing a windows phone app that communicates with a network player. I have a static instance of my communication class in my App class so all the forms can share the connection, and all my forms subscribe to it and process results within that form. From a main menu you can choose one type of source and it opens a file browsing form that refreshes a listbox as you navigate, cancels the back button and refreshes the new contents to simulate file navigation until you are the root folder. The app doesn't know if you're clicking on a file or folder, it gets a network message when media starts playing and watch for that and then navigate to a "play" form. I had been using all .Navigate's for this until now and it worked great until I added another branch off the main menu for a new source. Although the new source is completely different, the device sends a lot of the same generic commands which just mean something else in the current context. After visiting the my file browser form and going to my new source, a play command from the network, which means something else now, would cause my to jump into my old "play" form from the previous source as if I was still on the file browser form, which isn't intended.
So I've tried many things and have it kind of working now but it's message and I lose some features. Currently I changed from using all .navigates, also in the back button override, to trying to use the stack and navigate.goback's. I pass variables when needed using globals in App and unhook my net listeners from the form, goback, and then connect them in the new form's listeners in it' navigatedto. I think there is timing issue though as in some cases I needed to send a command to the media box as it's changing and it ended up triggering the wrong event handler again. I think the easiest solution, if possible, and they way I though it would work is if each time I navigated from the form it old one, it's handlers, etc were all destroyed and I didn't have to use the stack at all, handling all the back buttons myself.
I know that's a long description and thanks if you made it this far, hopefully it made some kind of sense. Does anyone have any suggestions on what I can do?
As a side note I'm a long time self-taught VB programmer who has been stuck in .net 2.0/winforms and I've just now made the move to C#, OOPs, and XAML to write my first Windows Phone app so it's likely I'm doing something stupid or overlooking something obvious...

It is likely because something has retained reference to the form. The most common cause is event handlers.
So, if your static class exposes an event, and you subscribe to that event in a form, you must unsubscribe from the event when your form closes / navigates, otherwise the form will remain in memory....
If that isn't the case, look for something else that is acquiring a reference to your form and not releasing it.

Most likely the problem is based on a bad application architecture, when it comes to handling commands send from the UI.
When you say 'sends a lot of the same generic commands which just mean something else in the current context.' you most likely reveal the source of the problem.
As a workaround, you can define an interface, that your communication class implements. Each form has it's own method it calls on a communication class instance.
If you indeed receive a command from a phone page, that is no longer in view, just don't process it.
You can store the navigation history to always know what page is the only one allowed to send commands to a communication class.