If anyone has seen this happen, please let me know -- I have Googled the entire Internet it seems, but haven't found anything similar. This problem has happened to me twice in similar situations -- or am I imagining this?? The scenerio: When adding/moving around a hard drive or a CD-ROM to a system, I have accidentally left both the CD-ROM and the hard drive jumpers in the Master position (or both in the Slave, I'm not sure which) on the same IDE channel. Afterwards, upon the next boot, I have communicated with the CD-ROM, installing software in each case... first time it was a CD burning program, the second time it was Windows 2000... at some point things weren't quite right and I discovered my jumpering error and fixed it. In case #1, Windows 98 on the hard drive got corrupted and wouldn't boot. Damaged registry I think. In case #2, the hard drive is now not recognized by the BIOS... EXCEPT when I jumper it to 32GB max!!... then it sees the drive, the model, the size, but does not recognize a logical drive (as if it was not formatted -- which it was [NTFS] -- the term it uses is "unallocated"). This just happened, and it's not my data, so I'm a bit desparate to understand what has happend to know how to proceed with recovery. So... my basic question is this: Has anyone experienced jumper settings causing corruption to a drive, especially when a CD-ROM drive is involved? If so, why does this happen? And why can the drive be seen in 32GB mode while it can't with normal jumpering? I've searched to try and find out EXACTLY what happens across the interface when the BIOS detects a drive... any help there as well? Thanks for any help anyone can give me.