Think I found the bad memory stick, how to run Memtest86 to check it?

This should help
Guide to using Memtest86+ - Geeks to Go Forums

or Hopefully this will help
www.sevenforums.com/tutorials/105647-ram-test-memtest86.html

Test all for 8 passes, then with a know good stick test each slot for 4 passes.
If a stick is bad test each separately.

JohnnyScience said:

Do I have to take the other 3 out & run the disk, or is there a way to run all together and I can pick which memory slot for it to check & run diagnostics on?

If you want to test the bad stick, you'll have to run memtest with only that stick. There's no way to tell memtest which sticks to test; it tests every stick that's installed.