Now a days a computer virus just wont make your pc crash noooooooooo they have become much more advanced. Here are some tips and some ideas on how to better protect yourself:

How to tell, what to do if computer is infected (AP)

Computer-virus infections don't cause your machine to crash anymore.

Nowadays, the criminals behind the infections usually want your computer operating in top form so you don't know something's wrong. That way, they can log your keystrokes and steal any passwords or credit-card numbers you enter at Web sites, or they can link your infected computer with others to send out spam.

Not only will they tell you what to look for but how to better protect yourself and your private data!

Here are two threads that go into how to better protect yourself on the web:
Recommended Antivirus Software

Free software protection