Multiple Threads Starting Up Spontaneously

Hi

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.

THANKS!