I've really messed up a computer.

It all started with a error message in Internet Explorer 7 about a psapi.dll file.  The research I found said to rename the file to psapiold.dll and reboot.

Oops...now when I reboot, I get a Fatal Stop error:

STOP: c000021a {Fatal System Error}
The Windows Logon Process system process terminated unexpectedly with a status of 0xc0000034 (0x00000000 0x0000000)
The system has been shutdown.

So I booted with the repair option from the Windows CD.  From the C:\> prompt, I type in cd windows and get 'The path or file specified is not valid.'  I get that message for everything that I type in.

So I typed in C:\> dir and I get
'An error occurred during the directory enumeration'

Am I up the creek without a paddle?  Is this system recoverable?  Can anyone help me please?

Thank you.

I don't know if this makes matters worse, but the Hard drive is Encrypted through Guardian Edge.

If the hard drive is encrypted then you will need to use Guardian Edge's software to read the data, otherwise there's no way to repair it.

There may be a pre-install driver for Windows XP, but I'm not sure.