Go to the Windows Update and download this (it takes over 5 hours, but is so worth it) It makes your PC more secure against viruses and hackers. This is so good. WINDOWS SERVICE PACK 2
My computer got a virus and crashed last month-so I installed this because that was so horrible.
Also, get Norton anti-virus and scan weekly. You can't be too careful. Don't be afraid of the internet-but be careful and take precautions.