the truth is there are viruzes that do such thing,,,
here's what you should do...
FIND a good ANTIVIRUZ... i would recommend AVG since its free and may be upgraded..
heres the link
http://free.avg.com/download?prd=afeafter downloading the file... follow these simple steps
1. click start
2. choose run
3. type MSCONFIG
4. choose BOOT INI tab
5. check /SAFEBOOT
6. Choose restart computer
after doing these steps youll find your PC entering safemode..
Once inside safemode heres what to do...
1. uninstall your current antiviruz software
2. install free AVG 8.0
3. run a full system scan
wait till it gets all the viruzes on your system
after scanning access the MSCONFIG.. uncheck /SAFEBOOT
and then reboot.
why you need to enter safemode??
safemode utilizes the pc resources for diagnostics by loading only the important components of the Windows OS to function properly,, viruzes are exempted, if they are not loaded then they can't run their dcript, if they acn't run script they can do no harm..