I had the same problem
The hard drive May not have been fromatted
Test it on a Win 98 Boot Floppy
Get it from http://www.bootdisk.com
select WIN98 SE OEM
I thought I had XP on my drive, but when I downloaded a WIN 98 Boot Disk, there was no Drive C: so it became the RAM drive.
I booted from a Win XP professional CD, and it looks to be working.
Formatting as NTFS 1 Partition
Only problem is I wanted it to be a WIN 98 PC.
If I dont update this within 2 hours, you can assume that the NVIDIA Boot Agent means the HDD is not formatted.
The odd thing is I tried to format the drive with a Western Digital Floppy & it did not want to know.