OK. So, apparently Windows XP Home decided to one day get stuck at the "Windows is starting up..." screen. This is just before you see "Welcome", then the desktop if there's no login password required.
Here's the check list:
- Hard disk diagnostic? No problems.
- chkdsk /r? *sigh* the setup CD doesn't seem to have drivers for the SATA controller on this particular machine, so I had to run this from another machine with Windows XP. But, it seems to be OK.
- RAM? Passed with flying colors!
- Asked Google? Yep, there's a few leads, but nothing that helped resolve the issue at hand :-(
The solution I found? It's some sort of corruption with ntuser.dat. I boot into Hardy LiveCD and swapped out the ntuser.dat file with the backup copy in %systemroot%/repair. Afterwards, Windows XP was booting fine again. I still don't really know what's in ntuser.dat that could have caused this, but at least the PC is usable again.
The downside of doing this is, of course, that all user profile stuff gets "reset" to the factory state. This includes wallpaper, desktop icons, and apparently some user specific settings in certain software. MS Office needed to reconfigure itself the first time you fired it up, but after that it's back to normal again.
I could import ntuser.dat back into the registry, but it caused a BSOD with stop 0x51. I had to repeat the "reset" process again to resolve that one. I think I better just take what little success I can out of this