My computer has been just shutting off on it's own. I felt the hard drive case and it's not warm. Any ideas?

When it does this I have to reset the switch in the back, wait 10 seconds, and turn it back on to reboot. I've blown it out with a can of air, but it will still shut down periodically. Some days it's after an hour and then sometimes it won't do it at all. Any ideas?My computer has been just shutting off on it's own. I felt the hard drive case and it's not warm. Any ideas?
i have fix a lot of computers with that problem. that is you power supply, but not worry you can buy a new one as low as $20.00 up on http://www.tigerdirect.com http://www.compusa.com http://www.pcconnection.com or just go to a store like Best Buy or a sotre where you can buy computer hadrware. you problem is the power supply. good luckMy computer has been just shutting off on it's own. I felt the hard drive case and it's not warm. Any ideas?
The usual causes for random shutdowns are:


1)Overheating triggers auto-shutdown to protect the CPU;


2)Memory module going bad;


3)Power supply going bad.