Approximately once every 6 months or so. I last reinstalled back in September 2003 but I've had some problems that definitely can only be fixed with a reinstall. I'm using Windows XP Professional as well. I've just not had the time, or desire, to go through all that again. Plus it isn't working all that bad right now, just a few quirks here and there.
BTW, anyone else have this problem? When calling Microsoft to get your unlock code for XP, do they give you a hard time? I know they technically can't due to the legal issues with the courts. At one point they were told that they must provide the unlock codes as long as the registration code you give them is legit. And they must do it without hassle. But every time I call, they ask why I have to reinstall Windows. I usually respond by reminding them of their fine products and how well
they work. It gets them to give me that unlock code though. :)
