SQL SERVER 2005 SP2 post upgrade issue

I've just upgraded to SP2 for SQL Server 2005 STD Edition on Win
Server 2003 Ent.

Since the upgrade I cant get MS SQL Server Management Studio to work,
I keep getting the following error:


Package 'Microsoft SQL Server Object Explorer' failed to load.


I have tried reinstalling the client tools/utils with the following :
start /wait "C:\SQL Server 2005 Standard\Disk 1\"setup.exe /qb
REINSTALL=SQL_Tools90 REINSTALLMODE=OMUS, but I still get the error
msg above.


MS SQL Server Management Studio runs on other machines and I can
connect to the server in question and manage it, but I'd like the
Management tools to work on the actual server.


All other SQL Components appear to be functioning correctly and have
no issues.


Anyone experienced this before?


Thx In Advance.