regardless of what people say bout removing partitions etc, I had the exact same problem
I put in XP Pro cd...deleted all partitions that were on the drive through the bluescreen install page, and was left with unpartitioned space, i installed on this and chose to format it with FAT32 (not quick). all was installed, and restarted PC, and HOME & PRO option came up. I was fuming. I cbf formatting all again, so i just edited the boot.ini to not give the option. Or you can change the diaglog screen, so instead of showing 30 seconds to make a choice, change it to 0. The screen wont even show and it will boot XP PRO.