Help!!

My latitude laptop was infected with Spywareremover2009, which wasn't dangerous but very annoying. Spybot couldn't remove it, so I downloaded the latest windows tools and ran those.

After this the laptop booted up ok, got to the XP password screen, logged in as normal but immediately logs out again.

I have reloaded windows in repair mode, but it is the same.

I have tried to return to the restore point but that's the same also!

Does anyone have any thoughts on my next move? I have a lot of data on the machine which isn't backed up (yes I know!) so I would like to try and keep it if possible. I am contemplating writing as much as i can to CD-r in DOS mode, or possibly moving all data to drive D (I have dual HDDs) and then reinstalling windows from scratch.

Am I missing something simple? or can anyone think of a simpler fix for this mess?

thanks in anticipation.