The only Mircosoft OS I've had problems with was Windows 98 (SE or not). Windows 98 was the worst (I've never had the privelage of owning ME 😉 ). Every 6 months or so I had to format and reinstall. It never mattered how much I used the computer - it was just like clockwork; the 6 month routine.
Since then I've had Windows 2k and once a few issues were ironed out through driver updates, BIOS patches, and a few software updates - the system is rock solid. I have a few friends that would testify to that about their systems too. After you get the bugs out of 2k/XP that straight 32-bit kernel really makes a difference over 9x/ME.
Anyways, I understand a lot of people are constantly installing/uninstalling software/demos. I'm very picky with what software goes on my system. I read reviews and user-feedback to find potential problems (mainly off of these forums) before I install. I'm not one that likes to install unnecessary software or stuff that might just sit on the hard drive. Also I'm the only one using this computer in the household so I guess it's "taken care of". I have a few IE windows, Outlook, a couple of Audigy applets, AIM, ATI MMC, FreeCell ( 🙂 ), PSP7, ACDsee, and MusicMatch 6 always running in on my computer (it almost never gets rebooted). When I play a game I close everything. Every now and then (say once a month) an IE window will crash but I just click "END NOW" and I'm all set.
I guess if you try to screw up your computer (but who does?!?) then your going to screw it up. If you use caution with software you download and install then your chances of having less headaches is proven in time.