Yes to above two post.
Suggestion - First sort out memory. Recommend you down load a Bootable copy of Memtest86 (iso) and create a bootable CD. Memtest is also included on Ultimate Boot Disk which contains a collection of handy utilities.
Boot to the CD to verify your memory is stable. When stable, then reinstall your XP - Reason, with memory errors you have no ideal if critical files have errors in them.
Once you have sorted out memory, AND reinstalled operating system download and install prime 95. Seems to be a better program for checking your memory, also checks cpu for stability. A bonus feature, it will load your system so that you can verify (a) PSU outputs good under load and (b) no temperature issues. You can use cpuid HWMonitor to monitor voltages and temperatures.