I built myself a new PC a few months ago. It's been working fine in general until about a month ago, when one day, during startup, the PC just locked up. I thought that it was a virus or something like that, so I formatted the computer and reinstalled Windows XP. As it turned out, however, the problem didn't go away. Now, occasionally even when doing something as simple as surfing Firefox results in either the computer stuttering or locking up. I'm beginning to suspect that my RAM is dying. Could it be the RAM, or something else?