sadly, the only "safe" way to install SP2 is immediatelly after a fresh install of XP, otherwise programs will or may become unusable. Even if a program is installed following the install of SP2, and SP2 wasn't installed immediatelly after XP, the problem still occurs. (in other words, you had the computer runing for weeks/months/years before installing SP2)
<{POST_SNAPBACK}>
Not true.
WinXP has been happily installed on my computer for over a year now and after I installed SP2, *everything* is working as it should.