Hello Ksmgangsta

Welcome to PCHF
Does firefox.exe show up in the process tab as all lowercase letters with no spaces? If it looks exactly like " firefox.exe ", then it most likely isn't malicious software. If it is all capital letters or has a capital F, or has spaces in it, then it may be a virus/spyware.
If it looks normal, try uninstalling firefox (backup your favorites first if you want to save them). After you uninstall firefox, run CCleaner. CCleaner is a free tool, and you can get it at the link I have at the bottom of my post. Run both the temp file cleaner (which is the cleaner button) and the registry cleaner (which is the registry button). To run the registry cleaner, click scan for issues, then when it is done scanning, click fix selected issues.
When you run the registry cleaner you may want to back your registry up, but I never bother backing up. I have run CCleaner on hundreds of computers in both XP and Vista with the default settings and never had a registry problem.
After you run CCleaner, try reinstalling firefox and see if it causes the same issue.
Let me know what happens and we will go from there.
