SP2 for Windows XP fixed many holes in the OS. This means that software taking advantage of those holes, or certain "assumed" behaviors, go nuts after the upgrade is applied.

Before I upgraded to SP2 I did several things:

1. I waited a while to see what problems others have had. As others here have stated, this is always good advice with MS.

2. I read the instructions. MS made it very clear that you MUST remove all spyware, adware, and viruses before doing the upgrade. I did a full "deep" virus scan and ran boh Ad-Aware and SpyBot S&D.

3. I looked for older software that might not work. That turned up an old TWAIN driver that I updated. When Nikon says that their software is not compatible with XP2 you should have listened.

4. I installed XP2 and have not had any problems at all.