I never ran memtest to its completion. I always run it for one full pass on each stick individually (so I know which one is bad). After one pass, if there are no errors reported, I quit the pgm.
Correct, memtest loads itself fully into a small portion of memory. When nearing finish, it moves itself to good memory in order to test the portion it was previously in. You can remove the CD as soon as the pgm starts checking memory.
Thinking back... i seem to remember having a system that had trouble running memtest too. It's been a long time, so I don't remember much other than I had to resort to using the Memory Diagnostics Tool instead. http://windows.microsoft.com/en-us/windows7/diagnosing-memory-problems-on-your-computer