Thanks for helping. I got a iMac a little over a year ago. For some reason the hard drive crashed, I don't know why. I got DiskWarrior and was able to get data off the drive (Mac wouldn't start up, just got the grey screen). Finally, I erased the hard drive and reinstalled OS X 10.5, but for some reason I still get the grey screen and after about 5 minutes of that get the flashing folder with a question mark. I tried resetting the PRAM and that didn't do anything. I run the disk checkes and permissions checks off the OS X disk and it says everything is valid. For some reason I think it just doesn't recognize the hard drive in the machine. In the Disk Utility it keeps coming up with the hard drive titled as "Untitled" or "disk0s12" Anyone have any suggestions on what to try next? Thanks for reading and helping.