pc in ded

[dirmaster0]

Get a replacement HD, resinstall OS, then hook up the failed HD inside the computer and open command prompt (assuming its Windows), find out the drive letter of the bad HD and run this command (will use D:\ as example)

chkdsk d: /f /r

If you see any bad sectors after it completes the 5 stages of scanning you know the HD is going bad--chkdsk could fix simple boot issues as well (less than half the time). If it does not complete the chkdsk (through the various stages or takes days to complete) you know theres something physical going wrong with the HD. At that point you could use spinrite to try to overwrite the bad sectors of the HD (1's and 0's) for a chance at recovering the usability of the HD. If you notice any sort of loud clicking or abnormal noises emitting from the HD, thats another tell tale sign of HD failure.

If your computer is still under warranty, contact the distributor or the manufacturer of the HD for a possible RMA claim.

Note that a rescue disk would not fix a HD failure as rescue discs have to do with OS recovery, not issues outside of the OS (bad sectors on HD for instance) and could only be used if the OS became corrupt.

If you happened to have had important data (personal, financial or tax info) that you absolutely need recovered from the HD, you could contact a forensic data recovery company (in which they will dismantle your HD and scan the HD platters sector by sector to recover irretrievable files, after which you would purchase back your data and get it sent back on an external HD, USB Drive, or DVD disc.

Now, if the issue is related to the OS (computer is able to see the HD in BIOS, and youre able to somehow get into safe mode) you could try running chkdsk on the HD and then run the following command in command prompt (run as admin)

sfc /scannow

System file checker will scan the integrity of the current build of the operating system, if it finds issues it will attempt repairs--if it doesnt fix the issues in order to boot normally you could try Combofix as a last resort, or run another chkdsk prior to this.
Good luck!