XP Pro SP1 update failure

[Anton]

I was updating my friends computer to XP pro service pack
1 and it failed. bad news. windows wont boot fully. it
goes all the way up until the logon screen, then shuts the
computer down!!!

any suggestions on how to recover this?

 

[Jupiter Jones [MVP]]

Anton;
Reboot tapping F8 each second.
Select Safe Mode at the menu.
Log in as Administrator.
Then go to Add/Remove Programs and uninstall SP1.

If that fails, reboot tapping F8.
This time choose Last Known Good Configuration.

If that fails, perform a Repair Installation:
http://www3.telus.net/dandemar/repaxp.htm

Follow this to install SP1:
http://www3.telus.net/dandemar/spackins.htm