So just I stood up pulling the power cord and knocking my computer off my desk and now it won't work. It automatically said something about shutting down because my computer might be at risk. When I try to restart it it goes to the safe mode start up screen and no matter which option I choose it begins to start up and then turns blue showing:
STOP: c000021 Unknown Hard Error

It sounds like the hard drive is not spinning much like it usually does when I first start my computer and I'm guessing something came loose. I was wondering if it sounds like it should be easily fixable or if my computer is done. I'm currently studying abroad in Spain and really need my computer so any help would be really appreciated.

Hello Barcaunc,
You did not' state the OS you are running I am going to assume XP plz let me know if this is incorrect.

Your error is caused by a necessary registry hive that could not be loaded because it is either missing or corrupted (most likely your system was writing to this file when it powered off).

It is a long shot but first I would attempt to boot with the last known good profile. To access this utility, reboot your computer and immediately begin tapping the F8 key. Then select "Last Known Good" and follow the prompts.

If that does not work, follow the steps in this MS article to recover your registry.


I am running XP and the last known configuration doesn't work so I'm going to try the link but I got my computer through school and I don't have the Windows disc and I'm in Spain so if you have any suggestions about how to go about doing that I'd appreciate it. O and the error message was actually c0000221 not c000021. Thanks for the help.

Does the complete error message list a specific dll, like c:\windows\system32\ntdll.dll? Here is a link to MS site talking about your error

Although without a XP disk there is not a lot you are going to be able to do. Can you get a XP disk from anyone?

p.s. I wish I was in Spain right now!!


Yea that is the exact file that it names. So I need to find just any windows XP cd and then follow the directions in the articles?

Yep make sure it is the same version i.e. Home, Professional, or Media..... You will be able to execute the steps in the article with the same version of the OS.
If you have to reload the OS you will need to track down a OEM version of your XP in order to use the license key you have on your system. Most schools purchase the license with the computer so if you have a license sticker on your computer it is an OEM version.
If you get stuck with the steps in the article let me know….. You will want to use the article in post #4 and you can ignore the other links.