XP station Virus can't sync or execute.

I have an SBS 2003 with about 25 XP clients.  One of the clients got a virus.  The symptoms were I couldn't execute any cleanup/spyware/anti-virus exe's that were installed.  It gave me this error:  "Windows cannot access the specified device, path, or file.  You may not have the appropriate permissions to access the item."  I finally got Malware-bytes and Combo Fix to run and got all the infected files out after a few rounds; I think.  

However, the damage remains.  I cannot sync with my SBS even though I have a network and an internet connection. When I try, it wants to use a dial-up connection.  

There are still some files I cannot execute, and while I could fix them one-by-one, I want to know if there is a universal fix.

It will not let me do a system restore to a previous point.  I was also going to format and start over, but the windows XP 3 install CD won't even boot.  

Norton Internet Security is installed, but so far it has just gotten in the way.

Any ideas????