Win 2000 keeps rebooting after Hitman Pro scan

A friend of mine's pc was totally infected with spyware, mallware, all kinds of Virusses , keyloggers, browser hijacks... the whole lot! So I decided to scan with the Latest Hitman Pro version to sort most of these problems out. After a reboot, I got to the log on screen, but when I log in,I get a message that there was sometihing wrong with 'logon.exe' and it keeps rebooting, same message every time, rebooring every time.

Now, I was so stupid not to backup his documents and settings, is there any way I can still backup his drive to MY computer, by plugging it in as a slave drive? I run Win XP, the infected drive win 2000...

Please help me out! I don't want my friend to lose all of his pictures and documents...

 

http://www.sophos.com/virusinfo/analyses/trojgolona.html

 

I appreciate for pointing me out to that... but how could I edit the registry key if windows won't even boot?