XP, 2k, or 98?
I do my recording in Win2k. It's stable and does a better job of memory management. No question.. hands down.. 2k is a much more stable OS than 98 or ME.
BUT.. OS stability is only the first step toward having a good DAW. There must be driver support for your hardware. Many sound card manufacturers (and others) are frustratingly behind the times in terms of driver support. Driver support is always the first thing to check into before upgrading your OS.
tj