I tried to upgrade a laptop to SP3, which broke it. I later found out SP3 doesn't work on that 2002 laptop. I can't uninstall SP3, or fix SP2, because the hard drive is now not detected during setup (I've read that's the problem you get). I put the hard drive in a USB drive case and plugged it into my other laptop, and I can read (& write to) the disk okay. (The hard drive won't fit in my other laptop, so I'm using USB.) I need to get that disk back to SP2, or fix whatever files got screwed up causing the disk to not be recognized. I don't want to do a re-install as there are 80GB of files on it I need, and they won't fit on the HD of my other laptop, and also because I no longer have some of the install CDs for software on it. What do I need to do to fix that drive from my other laptop? (I don't want my working laptop (XP SP3) to get screwed with by putting an SP2 disk in the CD drive, or the non-o/s data on the other hard drive screwed with.)
I'd recommend putting the drive back in the original laptop and installing XP (with slipstreamed SP2 if possible) over top of the existing installation, without formatting. This should get the OS working again, and theoretically will retain your applications and application settings. Though I'd still recommend backing up important data - just to be on the safe side.