Windows 2003 server - How to prevent defacing?
 

When running a webserver, Windows 2003 server as we do ...
We had several hosting accounts defaced the last couple days.
All service packs has been run, and even the IIS lockdown tool.
Yet some pricks have been defacing lots of pages ruining the reputation and all. Is there a golden way to prevent this?
Tried to seek MS tech for this issue, but yet no clue.
Server is behind HW firewall and the only ports open are the common ones, 80, 21 and so on.

Can anyone recommend a good port scanning tool, security scanning tool, whatever to prevent this shit? Or perhaps a golden tool?