before you do that post virus on forum someone might be able to help if not hear is how to reinstall windows.
firstly make sure you have the windows key it should be on a sticker on the pc case,
then boot into bios to do this boot pc and keep pushing the del keywhen in bios find the first boot device and set it to cdrom then open your cd rom and place your windows cd in the tray hit exit and save the draw will close and the pc will reboot and say press any key to boot from cd so push a key if you are running a sata drive you will have to push f6 when prompted and it will ask you for a floppy with the drivers on,
then just follow the onscreen instructions one last thing after it has formatted and copyed files it will boot your pc down again it will say press any key to boot from cd dont just leave it and it will start to install windows when all is finished dont forget to go back into bios to set first boot device to your hard drive, good luck