XP install troubles

My problem is that I tried to install windows XP as a upgrade to Millennium and things went good until days later I tried to install the XP service pack 1 that I had downloaded. Things all went well again until windows rebooted and all I got was a black screen and a white cursor in the upper left hand corner. I tried rebooting several times and nothing.Than I tried to go to go to safe mode and no luck there. I can install 98 SE or Millennium but when I try to upgrade to XP I get to the part where it says starting windows setup and than I get this error. "An unexpected error {o} occurred at line 1768 in d:\xpclient\base\boot\setup\arcdisp.c." press any key to continue. After that I choose the option to abort xp setup and it returned me to Millennium. After that I did an fdisk and formatted C: drive. also checked for a virus and replaced my copy of the mbr. Than tried it again five more times with the same outcome each time.
I have done this before with no problem on the computer..I have three separate hard drives on this computer and I can't do it on any of them. Its an 800Megz. Gateway. With 256 megs of ram with a 2gig.12gig.and 40gig. hard drive. I have tried both my copies of XP Home Edition and my XP Professional Edition to no avail. Any help that I should get would be appreciated so much.

 

I'd say this is your problem Butch

 

 
 
You will have much better luck if you just boot from the XP CD. Right after pressing F8 to agree to the license, you will have the option of deleting, making, and resizing partitions.

Format and remove everything from the drive and continue with a fresh XP installation.