Snyder81,
Your BX6 2.0 doesn't directly support that WD 120GB hard drive. The latest released BIOS for that motherboard is dated sometime in April 2000 - and 120GB IDE hard drives didn't exist at that time.
As it turns out, that latest released BIOS doesn't support hard drives over 64GB, and the BX6 2.0 only supports Ultra ATA/33. So you will need to buy an Ultra ATA/100 PCI controller card for your system.
BTW, the WD 120GB hard drive comes in two versions - one with a 2MB cache (WD1200BB), the other with an 8MB cache (WD1200JB). Both use an Ultra ATA/100 interface.
cya l8r