Windows Vista Vista: Windows Security Center Problem

As my Norton Internet Security subscription had expired, I uninstalled it, and replaced it with Comodo Firewall, and AVG free virus scan.

I noticed that after uninstalling NIS 2007 both Vista Update, and the Windows Security Centre ceased to work.

I have got the update working again (had to clear windows/softwaredistribution).

WSC, is not recognising my new firewall or av software. and is also having trouble turning on windows defender.

I have 5 other pc's with exact same software, this one is the only one causing trouble.

Any ideas?

 

When I try turning on Windows Defender from WSC, its checks for updates, the status bar gets to like 5 %, the it says no updates and closes, however defender stays offline.

Is there any way to reinstall WSC without reinstalling the entire OS?