Question : Problem: Windows memory diagnostic reports errors - what next?

I have a Dell Dimension 4400.  I was away from the office for about a week, and upon returning today, it has been rebooting itself every 20-30 minutes or so.  I am not running anything, mostly it sits as a part of a network, acting as a print server, ACT server, etc.

The Windows error reporting directed me to a memory error, and a microsoft memory diagnostic.  I ran the diagnostic, but am unsure what to do with the results.  There was a failure on the first pass, on the CHCKR3 test, but not on subsequent passes.  Other tests failed on pass 2 [WINVC], and others on pass 3 [MATS+, INVC].  Everything succeeded on pass 4 and 5; on pass 6, Stride6 failed.

About a month ago, I upgraded memory, replacing the memory it had (2x256) with two 512 Kingston modules, using the correct modules for the computer.  It has not had a problem before today.

What do I do next?

Answer : Problem: Windows memory diagnostic reports errors - what next?

Try reseating the RAM. If still problematic, try memtest:

http://www.memtest86.com/

Let it run for a good while.  If it finds errors, you will need to check which stick of RAM is faulty. The RAM should still be under warranty, so you can return it and get a replacement.