Computer Virus ? Advise ?

Comp. is only about 3 months old. Has the latest Norton Antivirus and Webroot Spysweeper and good cookie cleaner and so on. I thought it was basically virus proof. But I have been told I have a virus and it will cost $249.00 to repair. Computer is acting haywire and I don't know where to start.

I have already reset system to a previous date but didn't help.

Any advise ?

How do I find anything out without taking it in ?

Additional Details

1 minute ago

Anytime I run Nortons or the SpySweep It says no threats or viruses detected.

But the comp. is only running good for about 15min. at a time.

Until now I have never even had to re-boot before.

Computer Virus ? Advise ?panda

It might not be a virus, there may just be bad ram. Why would it cost $250 for a virus repair? It's just a nasty software. You just need to find and delete it. You could also see if your system is getting hot, that often causes crashes and software glitches. You may even have a bug in your registry. Try a registry cleaner and repair utility. Try the link below for a free trial version. Good luck!

Computer Virus ? Advise ?suzuki

if it's gonna cost that much, i'd recommend backing up your system to an external hard drive, only about $40-$60 for a small one, then using your restore discs to set your computer back to manufacture defaults. you've only had your computer for about 3 months, so i'm guessing you still have them. even if you don't it's only $20, which way cheaper then $250.
Get Norton Anti-Virus Software and install. This will clear the Virus installed in your PC.
Update your anti-virus software or reformat your computer to completely clean your system.