Hard Drive not responding
I have a 2007 iMac that I have never had any problems with. I unplugged it for a couple of days to paint a desk and have now reconnected and restarted it. For some reason it no longer recognizes that the hard drive is there. Upon reboot, I see the gray Apple, a bar as if it were loading software, then a OSX Utilities display box shows up asking me if I want to restore from a Time Machine disk. I do have a 2 TB Time Machine backup but I can't load from it. Also, one of the selections in the display box is Disk Utilities. I did do a verify on the OSX disk and it seems to be working so it is there, but it doesn't show the whole 750 GB hard drive that is available. Any thoughts on what to do?
iMac, iOS 8.2