I am on a Mac so I am at a disadvantage:) in relating exactiy how on a PC; however, I know it is a very real problem for some. There are third party utilities, one being the free "memtest". This software has a version for the Mac and operates on the console; in other words the GUI is unixy. See http://www.memtest86.com/ However, before dealing with that I would check out Microsoft's Windows Memory Diagnostic: http://oca.microsoft.com/en/windiag.asp manowar