If it reboots on wake-from-sleep, it may have experienced a kernel panic. Use this article to look for a recent "suicide note" and post the text here for Readers to examine for clues:
What was this "virus" that you got? It's extremely unlikely that you were infected with any kind of malware, but a name would help immensely at figuring out whether that has any relevance.
As to the problem, can you describe it more precisely? Is it giving you a message asking you to restart? Or does it restart all by itself? Or is it becoming completely unresponsive, requiring you to force restart?
Regarding Apple Support, note that you can always choose to make an appointment at a Genius Bar at your nearest Apple Store and get the problem looked at for free. There are options. If you want to talk to someone on the phone and do not have AppleCare, though, then yes, you will have to pay a per-incident fee. I certainly would not call that fee "exorbitant gobs of money."