I had this happen to me. I finally found out what the problem AFTER I ripped out everything from my computer, i.e. sound card, NIC card, bought new HDD cables, disconnected my floppy drives.
The problem was....drum roll please.
My fricken compact flash card. I had my USB cable still connected with my compact flash card. After it checked the harddrive it went to see if it can boot or something from any other drives. I had a compact flash card so it thought it was a bootable or a bad sector on the disk. It was stuck reading every sector, I guess, but soon as I unplugged the USB cable, the sucker booted up right away like it is suppose to.
Do you have a compact flash card, USB drive or any other thing?
Soyo Dragon Ultra Platinum Edition powered by a P4 3.06GHz w/HT @ 533FSB
ATI Radeon X800Pro 256DDR <---Yeah!!! I finally got it!!!
1024MB PC3200, Creative Audigy LS, 2 x 40GB = 80GB RAID 0
Windows XP Pro, DOOM 3, CS, UT2004, BF1942 RtoR, CNC Generals
Finished Half-Life 2!!!!!!!!!!