[Cirerrek]

Not sure about the UNMOUNTABLE_BOOT_VOLUME problem as I have never encountered that error, although from your problem description it may be related to cable type.

UltraDMA/UltraATA: Also known as ATA/33, ATA/66, ATA/100, ATA/133, is a technology in newer IDE hard drives that allows for greater overall throughput.

Newer drives with UDMA capabilities can handle greater data througput, but to take advantage of this extra throughput, for ATA/66 and higher you need to have an 80 pin IDE cable instead of a 40 pin IDE cable. You can typically tell the 80 pin IDE cables from the 40 pin IDE cables by looking at the drive connectors at the ends of the cables. The 80 pin IDE cables will have blue connectors while the 40 pin IDE cables will have black connectors. There may be other obvious differences as well but I don't know of any off hand.

If you don't have the proper cable, then you can go into your BIOS and turn the DMA settings off for that particular drive and it should work with a 40 pin IDE cable as most of the IDE controllers are backwards compatible with older standards.