[SAcx]

The system cannot log you on . . .
I'm receiving the two following errors:

Error Message 1:
"The system cannot log you on due to the following error: Invalid access to memory location. Please try again or consult your system administrator."

Error Message 2:
"The system could not log you on. The server authenticating you reported an error (0xC000000BB). You can find further details in the event log. Please report this error to the system administrator."

The first error was receive after I reboot the PC, and then I receive the second message for every logon attempt thereafter. This is a business computer which resides and logs into a domain. It's running Windows XP Service Pack 2. We use simple username and password authentication and that's it.

This message started after the following occurred:
The user was working in an application and recieved a Reference memory error.

[SAcx]

Logged on with a domain admin account that did not have a profile cached onto the particular PC. I was able to log into the PC. Oce I did that I ran Microsoft Updates. Some of the updates failed (most of the Office 2003 updates) but the other were successful. Once I restarted the PC I was able to logon with the original users login.

[DLHI]

I had the same situation, using a business PC which logs into a domain.
I could not log on the machine using any domain account or a local admin account.

The 2 error messages were the same:
Error Message 1:
"The system cannot log you on due to the following error: Invalid access to memory location. Please try again or consult your system administrator."

Error Message 2:
"The system could not log you on. The server authenticating you reported an error (0xC000000BB). You can find further details in the event log. Please report this error to the system administrator."

Gained access by resetting the password local admin account using Cygwin. Proceeded to Windows Update. The update which seemed to solve the problem was XP SP3. Disjoined and rejoined the domain.

Not sure what the problem was, but while logged in with local admin account our Antivirus program was causing Microsoft OS error messages to continuously appear. After the update, no error OS popups. Problem could have been associated with update conflicts. The same timing with SAcx's post seems to support this.

Also, I made an imaged of the corrupted drive, which proved to be helpful for a restore during this MS escapade.