My computer shuts off for no apparent reason on it's own. Should I replace the hard drive? What

It has been doing this for about a couple of months. My bf put in new memory and an additional hard drive, but the problem still persists. Should i have the old (first hard drive) taken out...would that fix it. I've tried recovery disks, done maintenance, ran virus protections....

My computer shuts off for no apparent reason on it's own. Should I replace the hard drive? What to do?vista

A likely reason for this occurring is the system could be over-heating. Try cleaning the ducting for the fans %26 fans themselves, since dust %26 debris could be blocking them, causing the cooling system to operate less efficiently, thus removing less heat from the system.

My computer shuts off for no apparent reason on it's own. Should I replace the hard drive? What to do?antispyware

Usually when auto shutdown, the first thing that comes to my mind is the power supply unit, PSU. Either the PSU is about to reach the end of its lifespan or it couldn't take the extra load of the added ram and hard disk drive. Either way would meant the PSU might need replacement. But of course you're advise to test your system with another PSU to comfirm it rather than go get a new one immidately.

If the PSU needs replacement, then I think it would be better to get not just a new one, but one that is more powerful than the previous ones, with higher power rating.