|Since you can't logon, I have to assume you have no other accounts on this pc [something you should consider changing] and you don't have a xp cd.. your access is pretty limited.|
Here are some possible tacts;
Logon under safe mode. [most likely get same error]
At a friends house buy/download file recovery software and put it on a bootable device [cdrom] then recover your deleted files to the correct location(s).
Borrow a xp cd of the same type [home vs pro] and do a repair install. Sounds like you would need to go thru the registration process again.
Borrow a friends laptop to get your intenet installed in the meantime.