Steps for a full recovery:
1. Smack friend *REALLY REALLY* hard.
2. Make sure you have recent backups (he does make backups right?)
3. Format
4. Reinstall
5. Recover
6. Smack friend *REALLY REALLY* hard
7. Make sure he stops doing stupid things online with a nice smack to the head
8. Get a good anti-virus program and keep it up to date
9. Get a good firewall and keep it up to date
10. Make sure all security fixes have been applied
11. Smack friend *REALLY REALLY* hard
12. Tell friend to stop playing CS is he is not smart enough to not piss people off and keep his own machine secure.
(this is an expanded version of my Backup, Format, Reinstall, Restore (patent pending, copyrighted, trademarked, and graphitied) process.