I use XP (just switched from Home to Pro edition few months ago) and RSL500
was/is running just fine with or without DH+. And I do use masive editing when making upgrades etc on running equipment...
Anyway, here are some toughts:
Did you try to run some hardware tests to ensure memory and CPU are
all ok? In the past six months I've found memory problems on couple of PCs.
Removing affected module solved the problem. Simple test that cost's nothing
is to start many instances of large applications so that system memory will be
completely used up. If you have hardware problem, any program will crash
your PC. If you want to invest a bit you can buy Microscope (chances are
your local PC shop is using it to test their equipment).
Once you prove no hardware defects, check for resource conflicts. Maybe you
just have bad cable? I see the PCMK connectors broken quite often. (Some maintenance guys would rather blame it on not-working hardware than try
to use it and fix the problem...)