DB full - need to shrink (SQL Express 2008 R2 Express, VMware Vcenter)

Vcenter running SQL Express.  "VIM_VCDB" reached 10GB and so crashes Vcenter.

I'm trying to follow this guide:

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalI...

Currently, I got the SQL Mgmt Studio up on there, but it's not letting me get into the DB.

"The database VIM_VCDB is not accessible."

Thanks for all guidance.