Start\Run: Regedit
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Find the culprit in there. Delete it.
I very well think this is also in C:\WINDOWS\System 32
Go there.
Right click\Arrange Icons By\Modified
Idk if you have this but try anyways.
Tools\folder options\View Tab\Show pop-up description for folder and desktop items.
Then go to the bottom of the page, look for items that you think are viruses/spyware whatever that were made on the day that your problems started -OR- PRTSCR for me and post the picture here and let me look at it. Then do
Start\Run: Msconfig - make sure it's off in there. When the reboot screen comes up leave it up for a second. Go CTRL+ALT+DEL. Look for any stupid processes running and end them. As long as it isn't a system one you're probably fine.
http://www.answersthatwork.com/Tasklist_pages/tasklist.htm use that to search a process to see what it does. After you're sure it's not running, push Restart on the Msconfig thing.
After you restart, run the "HijackThis" program that I gave you, and look for anything -OR- PRTSCR that too for me.
I'll be back later.