Thanks for the thorough response. I didn't explain myself clearly, I apologize for that. As a side note, I have a fair amount of experience and have reinstalled Windows on dozens of machines, but I am not an expert or even a veteran by any means. I'm the friend "who knows computers."
The machine's symptoms were boot to welcome screen (where user selects profile). Upon selecting the profile (there was only one) the machine would flash the desktop (no icons) and then return to the Welcome screen saying "Saving settings . . ." and then sit there as if I had not clicked on anything. I could shut down, but never properly attain the desktop. Before this, the user said they had accidentally clicked on something while browsing and a bunch of pop-ups started showing up.
I figured it was a virus of some sort and my first order of business was to boot to Safe mode. Upon doing this, the safe mode boot (after selecting Safe Mode and not Safe Mode with prompt or network) was to boot to welcome screen and now show two profiles - Admin and the User. I've tried both profiles and both act as mentioned above - a quick flash of the desktop screen sans icons and then back to the welcome screen.
I can't say that I've seen this before, so I figured the virus messed up the HD royally. I then removed the boot HD, he has two in the machine, a second larger HD for maintaining his work, and put the boot HD into a USB HD kit to read it from another machine (also the User said there may be some data on the machine that he needed). So after checking the drive, it came up fine as an external USB drive, I put it back in and did a Win XP install (repair), this went fine (as far as I could tell), but upon final booting of the machine, it had the same behavior as mentioned above. Welcome Screen only.
So I said, bugger that. I bought and put in a new drive. I had to change BIOS to boot from CD. This worked fine an Win XP (full version) started to install. It wanted to format the new drive. Good. I chose NTFS and after formatting it copied over the Win XP installation files. After copying over the files, I get a 15 second (red bar) countdown that says it will reboot automatically. As I remember, this is normal. Upon reboot it starts using the files it copied over to HD.
Well, when it did reboot, the BIOS has the "Boot from CD: . . . ." message, which usually means press any key if you want to boot from CD. I didn't press anything but the system boots from the CD as if the driver were new. It wants to start the XP installation from the VERY beginning. So I went into BIOS and changed boot order again to HD first. This didn't change the outcome. So then I changed BIOS again to say HD only, and it still boots from CD.
I am starting to wonder if the Mobo IDE controller has gone bad. I think the mobo is about 4 years old. The user does not have the documentation for it.
What I currently still need to try:
Checking the original boot HD in another machine with a virus checker. (Another thing I noticed about the drive was in the Documents and Settings directory -where profiles are stored - the user had about 10 different profiles that looked like automatic bastardizations of his original name. Not sure how else to explain it. As if Win XP was trying to boot but couldn't so made a new profile similar to old one).
Removing battery from mobo - to reset BIOS.
The mobo has a second IDE controller slot (where his two DVD drives are attached). I thought I might detach these, and hook up original drive only to see if it can boot from that controller.
And to answer you question, I couldn't get into Safe mode, so that is what prompted all this other action. I may have a situation where a virus and a hardware failure are occurring at the same time.
Thanks again for reading and for helping!