Unable to connect in Multiplayer on PC

I've been playing this game since it released. It's had a few problems, but I can deal.

Now, after the last update, I am unable to connect. I'm getting the "Notice    Call of Duty: Black Ops server is not available at this time. Please try again later or visit"...  blah blah blah...

I have tried uninstalling and reinstalling twice... no go
I reset the router and checked settings... no go

I installed on a different PC and it works there. (I want to run it on the better PC)

What else is there to do? Is there a removal tool to ensure everything is clean?



Thanks for any help!