My computer keeps randomly shutting down. This is a problem...how can I fix it?

My computer keeps randomly shutting down. This is a problem...how can I fix it? I've had the PC about 2 months, and roadrunner about 5 weeks. It started happening about the time I got online. It happens once or twice a day, sometimes more or less. It's so random. It just shuts down as if someone pulled the... show more My computer keeps randomly shutting down. This is a problem...how can I fix it?
I've had the PC about 2 months, and roadrunner about 5 weeks. It started happening about the time I got online. It happens once or twice a day, sometimes more or less. It's so random. It just shuts down as if someone pulled the plug or hit the power button.

I thought it was a power problem so I bought a surge protector...that did nothing. I thought it was a virus...but my anti-virus scans pick up nothing.

HELP!!!
Update: Not getting a bsod...and currently i have a free antivirius called avg and windows antivirus.
11 answers 11