I have recently installed a P4 motherboard (1.7ghz) and when my PC is switched on, the HDD fails to power up. The HDD comes from a AMD based PC, so I know that it won't boot, but I can't understand why it doesn't power up ... I have tried a different HDD from a Pentium based PC and the same PROBLEM occurs ... can anyone help ?? ThanksCan anyone help with this ??Ok... So you installed a Hard DRIVE into a new system, and it's the only hard drive in the system? And you set it up as the Primary or CS? And it's connected to a a power plug which you assured is firmly seated... What exactly does it do? Can you see it in the BIOS? Tell us what you've done to troubleshoot.

Thanks.
It is the only hard drive ... there are two optical drives (that have now been detatched ... the same problem persists) I have checked all supply and IDE ribbon connections and the are all secure ... I have tried a different HDD ... same problem. It doesn't show in the BIOS. It is simply not POWERING up !!!do your other drives work? it might have shorted out or somethingBoth optical drives do work in a different PCWhat kind of hard drive is it? SATA? EIDE? UDMA?And if IDE, is a 40 or 80 conductor cable in USE? Are the IDE controllers enabled in the BIOS?