Ok, here's the score with O-Edit. It will run clockwork on XP, and it seems to be the best OS to run it on. It won't install on vista, but i have a Vista install that has been made by some clever chap that is very recent and i got it to open, however on my PC (and i have a good one) it was extremely slow, and i mean unuseable.
But that might have been fixed by now. As for Windows 7, i have no idea. I can look for my Vista download for you if i still have it and upload or link to it, but it's probably a waste of time. Hence why i've gone back to XP on my laptop, as i know it will work.
Their is a method to get the XP version to run on Vista.. all it involves is some command line stuff in CMD, though it can work, mostly you'll be very lucky if it solved your problem.