Unable to launch SQL Server Configuration Manager - WMI provider issue

Hoping you can help. I am having issues opening SQL Server Configuration Manager on Server 2k3 with the following error:

Cannot connect to WMI provider. You do not have permission or the server is unreachable. Note that you can only manage SQL Server 2005 with SQL Server Configuration Manager. Invalid class [0x80041010]

It would appear to be a wider issue than just SQL Server as I can't view system info using msinfo32, it says:

Access denied to Windows Management Instrumentation server on this computer. Have an administrator change your access permissions.

I'm logged in as domain admin however have tried this with local admin to the same results.

Running the mofcomp fix within C:\Program Files\Microsoft SQL Server\90\Shared\ yields an access denied message, and most forums seem to recommend running cmd as admin which I've done - no difference.

Any help would be greatly appreciated, I'm happy to give further information should you require it.