Yep, I've Seen Others With Issues But..
....After installing SP2 and SP3 on a couple hundred computers by now, and not having any of the issues mentioned, (primarily because I've prepared them all), I'll propose that it can only be the result of: 1. Faulty install of the original operating system. 2. Bad SP3 installation files. 3. Faulty install of hardware drivers. 4. Or bad hardware such as a hard drive that isn't working as designed.
It will be interesting to see how your troubleshooting goes, especially if you install the new operating system discs from scratch. Good luck.
Hope this helps.