Windows XP won't finish re-install

I’m running Windows XP SP 3 on a Dimension 8400; 1 GB RAM, 160 GB HDD.  BSOD shut down everything, and on reboot got another BSOD.  This happened several times, each time returning the same STOP hex addresses.  (I had not recently upgraded hardware or drivers.)  I tried booting to safe mode, but that was a no-go. I then removed the SATA HDD and connected it via USB to my laptop.  First I ran all kinds of virus/malware scans using at least 5 different programs, which essentially came back problem-free (other than typical registry issues of bad shortcuts, uninstalled programs, etc.).  Hooked up as my E: drive to the laptop, I could access the HDD without a problem; all my data appeared intact.

I then re-connected the HDD to my 8400, and tried to boot up.  Nothing.  I hit F12, and tried doing a repair installation (not the repair console) using the Dell XP SP2 reinstallation CD.  Somehow, that didn’t quite go as planned, and it looked like Windows was reinstalling and wiping the drive, so I manually interrupted the process (hard shutdown).  I started up again, and went through the same process, doing a repair install.  However I ended up with TWO copies of windows on my C: drive; the newer copy from the repair install worked, and opened as a brand new windows install (yet all my data was still there when I looked in windows explorer).  Perhaps stupidly, I then connected a portable HDD, which had been making regular backups using windows backup, and restored the windows settings using backup.  That got my desktop to appear as it did before the crash, but I got the “generic host for win32” error message.  Then I could not shutdown windows, resulting in another hard shutdown.  This happened several times (boot up, generic host, freeze).  Then windows wouldn’t boot again (I could hit F12 and see the 2 installed versions, but neither worked).  At one point I got into CHKDSK by accident, which said the drive was “dirty,” and it deleted some things and added some things, but I still couldn’t boot windows.   

I booted into the diagnostic partition and ran all the tests; many hours later, everything passed.  So I tried booting from the Dell XP SP2 reinstallation CD, again.  This time it only listed one windows version to try to repair install (the newer installation), so doing that eventually got me to Windows setup.  But as soon as that starts I get the “The file 'Asms' on Windows XP Professional CD-ROM is needed. Type the path where the file is located, and then click OK.”  No matter what path I type, nothing happens; the error box still stays up there.  I can’t boot into safe mode b/c setup isn’t complete.  So, now the second windows version won’t finish setup, and the original windows install freezes up at the black windows logo screen. After 4 days of this, I’m ready to pay MS the $60 to fix it over the phone…That, or a sledgehammer.