I've never upgraded my OS and don't see any reason to do it now. I'm typing on my win xp laptop, still works great. My desktop runs win 7 (came with the pc) configured to look like windows NT. All bells and whistles disabled, fast with a bunch of shortcuts, folders, basically everything directly on the desktop 1 click away (ok 2 clicks in windows)
Windows 7 runs great, though too much overhead for my laptop with 1gb memory. I only wish more programs would make use of the 64bits and multiple cores. No reason to upgrade yet.
Anyway I'm old, I still use TotalCommander, formerly known as Windows Commander, before that Norton Commander.







