I'd try another hard disk now.
I've tried repairing my desktop after it stopped working last week. It ran into a critical error of some kind and crashed and is unable to function properly when attempting to log in after rebooting it, and is giving various hard error messages. Among the failed repair attempts are: restoring from an earlier point in time, restoring from a backup system image, the automated Windows repair troubleshooting thing, resetting the computer to original settings with personal files and again without personal files, resetting to factory image with Dell backup and repair (that one has failed utterly-no image/options have ever shown up for me when attempting to use it in the past), command line scan and fix of hard drive, and probably a few others I'm forgetting about. There were consistent error messages of unsuccessfully completing whatever operation it was attempting and the changes were undone.
The computer is able to boot to the login screen successfully (which from what I've read/found so far is a good thing), so I'm able to run commands with the computer. Chkdsk has just led to loops of attempting and failing to fix whatever went wrong.
Some of the specific errors I've gotten have been (paraphrased)
"System restore failed, drive might be corrupt. Error (0x80070571)"
"ScanToPCActivationApp.exe - System error. Code cannot proceed because IPHLPAPI.DLL is missing."
(from the chkdsk I think) "40 KB of bad sectors found. Failed to transfer logged messages to the event log with status 50."
I'm not sure of the specs of the computer, but since I can run commands in the command line I can probably find out what they are if it's needed (and someone reminds me how)
Thanks in advance