Hi Richard,
Thank you for posting in Microsoft community!
I understand that you get an error message “Access violation at address 00000000” when you try to log in to your other account after
windows update. I will try to help you with the issue.
1)
Is the issue confined to any particular user account?
2)
Which anti-virus application do you use?
Method 1:
Step 1:
Could you check if the same issue occurs in safe mode?
Please follow the below link on how to boot the Computer in safe mode with networking.
http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode
If safe mode works, proceed with clean boot:
Step 2: Clean boot
Putting your system in clean boot state helps in identifying if any third party applications or startup items are causing the issue.
How to configure Windows 7 to start in a "clean boot" state
http://support.microsoft.com/kb/929135
Note: After troubleshooting, make sure to put the computer to start as usual as mentioned in Step 7 in the above KB article.
Method 3: Run a virus scan
http://www.microsoft.com/security/scanner/en-us/default.aspx
Note: Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.
Method 4: Create a new user account check if they work.
http://windows.microsoft.com/en-US/windows7/Create-a-user-account
If it works in a new user account, then you can consider the old user account as corrupt. You can check the link below on how to ‘Fix
a corrupted user profile’
http://windows.microsoft.com/en-US/windows7/fix-a-corrupted-user-profile
Let us know the status of the issue. I will be glad to provide you with the additional options available that you can utilize to get
the issue resolved
