What operating system are you using?
Personnally I've had no trouble with the editor having regularly used it for over a year...
One reason I'm sure is that I have 512Mb of RAM and a decent RAM manager.
If you are plugging 128 MB of RAM and using windows ME or 98 ensure you run as few as possible other programs at the same time. Certainly don't load civ3 and use the editor at the same time.
With the blue screen of death, it tells me that your OS is the problem as a crashing program doesn't cause XP Home Edition to need the computer to reboot.