RE: Windows XP
When I bought my last computer, it came with XP installed (Dell). This was only a month after XP was released. I could see some things that I really liked, but it was unstable and would not run many of my old (and very expensive) programs in spite of MS compatibility claims.
After fighting with it for a couple of months, I went back to a clean install of Win 98SE. The real problem here was finding Win98 drivers that would work with the new hardware (Win 98 was not supported for this computer by Dell). I finally got it all working and used Win98 for about a year.

Finally Microsoft came out with XP service pack #1 and I took a gamble and reinstalled XP (tremendous amount of time and work).
It has worked WITHOUT A HITCH and WITHOUT A CRASH ever since.
If you are having problems with XP, make sure you have Service Pack #1 installed.
And very important, don't ever use an upgrade, always a clean FULL install of any operating system.
Just a hint,
Walt