My computer keeps crashing, WHY?

my computer (4 yrs old compaq laptop) keeps crashing after 25-30 minutes of use, my best friend (super techie geek) said it might be a virus; but I got antivirus software %26 it said that there wasn't a known virus detected. What should I do?!? Help me plz

My computer keeps crashing, WHY?norton 360

Your PC may be overheating and need some internal cleaning. It's a fail-safe so it doesn't destroy itself. If the PC works fine while it's on then that's all I can think of.

Check the CPU fan, the power supply and any gunk on the motherboard, hope this helps.

My computer keeps crashing, WHY?photoshop

it depends on how long its been doing that and what kind of windows u r using.
That's really hard to diagnose without knowing exactly what is installed etc. Basically, if you have tons of different software installed and you never update your drivers - the software itself could cause this to happen. If you have the original disks you could start uninstalling programs, defragmenting the hard drive, updating the hardware drivers then reinstalling the software.

However, it could also be bad RAM. I have a desktop and a few years ago one of the RAM memory sticks went bad but I didn't know it. My computer crashed 100 times and it was the most frustrating thing ever. I finally replaced the RAM hoping that it was a bad stick, and sure enough - it was 100% thereafter.
OK