I just recently had this problem after I last tried to shut down my computer. Whenever I try to turn it on, it says that Windows has either had a hardware or software problem and that I can either start windows normally r use the System Recovery. Either way, it goes to the same default blue-background screen with an enlarged mouse, where I then get the following error message:

"LoadKey failed with error 999 (STHIVE#0)".

It then runs the Startup Repair, which never works. The following is the error from the diagnostic details from the Startup Repair:

Session details
---------------------
System Disk = \Device\Harddisk0
Windows directory = C:\Windows
AutoChk Run = 0
Number of root causes = 1

Test Performed:
---------------------
Name: Registry hives test
Result: Completed successfully. Error code = 0x0
Time taken = 109544 ms

Root cause found:
---------------------
Registry is corrupt.

Repair action: Registry roll back
Result: Completed successfully. Error code = 0x0
Time taken = 37721 ms

And from there, it goes through a list of checking everything and then has to restart to finish. Upon restarting, however, the exact same thing happens, where it finds the root cause to be the registry, it rolls the registry back, etc etc... so it simply wont fix itself.

My son was playing a game on it the night before, and started to bang on it because the wifi in our house sucks and he lagged out. I noticed exactly where he was banging, and it was in the bottom-left corner, RIGHT above the primary C drive (a second drive is located in the bottom-right, each drive having 160g of memory). What can I do to fix this? Is the problem what I think it is... that my son broke the drive?

It looks like you need a new drive. They are not designed to be banged on, specially while they are working.

I was afraid of that. Is there anything I can do at all? Because I kept trying to run different diagnostic repair tools and they often have different outcomes.

On Windows XP, run "chkdsk /R" from the command prompt, if you can boot into safe mode.
Or you could try formatting the drive (a full format not quick)by booting with your XP CD, and see if it will format, if it does, it will mark the faulty sectors as unusable. At this stage you have nothing to lose.
If you are using different operating system we need to know which one.
Also I'm assuming you are using an IDE hdd not a SATA, if not you need to say.

I'm using Vista, and I have 320GB 5400RPM SATA Dual Hard Drives (160GB x 2) in it. I'll try a full format with the vista CD.

You will need to use custom setup to get to disk management in Vista.

Ok, just started System Restore on Vista, and I chose a full factory restore. Cool thing is, it asked if I wanted to back everything up! I said yes, it scanned everything I wanted categorically (e-mails, movies, music, documents, etc), made a list on the recovery drive, then asked me where I wanted to store everything. I chose my D: drive, of course, and it's right now at 4% of creating the backup!!! So hopefully this will finally work and everything will be solved. Thanks again for the help, I'll post back if it succeeds.

It's at 22% now, going rather slow since it's getting every single program... including the useless, factory-installed ones... but at least it's working!

Everything back up, and I restarted my comp. Now, however, the same thing occurs, where "CHKDSK is verifying indexes (stage 2 of 3)..." it'll correct a few errors in some indexes, then sort an index, correct a few more, sort once more, then always stop at "28 percent complete. (4537 of 20143 index entries processed)". I'm guessing this means it's beyon repair at this point... well, at least the backup HOPEFULLY worked, no way to tell until I install an OS on my 2nd drive..