Memtest86 - A Stand-alone Memory Diagnostic
|Here's a great tool when you think your system
memory (ram) might be going bad. I used the floppy disk installer tool but
there's a CD based installer there also.
Website - Download - Quote from the website
Memtest86 is thorough, stand alone memory test for x86 architecture computers. BIOS based memory tests are a quick, cursory check and often miss many of the failures that are detected by Memtest86.