Hi AlexxStone and welcome.

Why do you think it is caused by a virus?  It could also be a corrupt hard drive or a hardware problem.

Did you make a set of Recovery discs when you first got your Vaio as prompted by Vaio Care?  If your hard drive is corrupted, this is the way to clear the hard drive and reinstall your system.  Try following "To Recover from Recovery Media" here: -

ftp://ftp.vaio-link.com/pub/manuals/RecoTS/2011Q1_TRG_EN.pdf

I presume you still see the Vaio Logo splashscreen when you turn the Vaio on?  Try tapping F10 repeatedly when you see this screen.  Does the Recovery software start?  Try following the "To Recover from the Recovery Area".

If you are still within the Warranty period, I would contact Vaio Support as if the cause is a faulty hard drive or mainboard, they will repair your Vaio under the guarantee.