Ok first off, yes, I am a noob to computers compared to the general population here. That being said, I can find my way around a computer fairly fine, and build them/take them apart. My roommate is much better with computers and he also could not solve my problem (he suggested this forum)... The problem: I bought a Seagate Barracuda 7200.11 ST3750330AS 750GB hard drive some months back and plopped it into a Gigabyte P35 (GA-EP35-DS3P) mobo without a problem. The drive was basically used for extra storage and had random crap on it, while a Western Digital was used for my OS. A couple days ago I swapped out the P35 for a Gigabyte X48 (X48-DS4) - (need some 4870 crossfire action), and didn't bother with a reinstall of windows. I just put the WD in and windows booted up without a hitch, albeit sans drivers. The drivers for the most part auto installed and then I installed some more drivers and I was back online, almost headache free... almost. Well the Seagate just won't show up in windows, and the system manager detects it and says it has no problems and is working fine. When I tell it to populate the drive it says it is unreadable. Since the drive has previously been populated I tried checking the bios and the bios detects it as well. I tried swapping out the Sata cables, moving it to different sata ports on the mobo, setting it as master, setting it as slave, and even tried it on a different computer. I used the old P35 mobo to make another computer with the same processor (Q6600) as the old configuration and used a new Western Digital for the OS. When I plop the Seagate into the P35 comp, I have the same problems. Bios detects the drive, windows system manager detects the drive, but the drive is not assigned a letter and is not accessible. If this is a simple problem, please excuse my noob-ness but I cannot figure it out. Sorry for the lengthy post, but I figured providing a detailed account of what I have tried might help. I have considered the possibility that the drive is trashed, but it seems unlikely given that I didn't kick it around after taking it out, and for the most part hard drives are fairly solid. Any help or suggestions would be much appreciated. Oh yeah, I know you're normally supposed to reinstall an OS after installing a new mobo, but WinXP worked so I decided against it. Since the HDD is for storage only, this shouldn't affect it's function in a different computer anyway.