As far as the virus...It's been a looooooong time since I have seen a virus that actually affects hardware. There used to be some virus' out there that could somehow do damage to your hard drive, but like I said, I haven't seen those in a very long time.
In order for a virus to do damage to hardware it would have to probably mess with the firmware on the hardware, so it really isn't damaging the hardware itself, but the software the hardware uses to communicate.
It is good you have decided to take it in since it is still under warrenty. Laptops are harder to troubleshoot because you can't just pop opne the case and dig around and replace parts until you find out what is wrong.
From your list of problems, it could be
1. Processor (overheating)
2. Harddrive (overheating, corrupt)
3. memory (probably not though)
4. Motherboard (less likely than first 2 but more likely than 3)
So as you can see, I HAVE NO IDEA.
But thought I would add my 2 cents about the virus to lessen your worries about that a little.