Activity Monitor can be found in the Object Explorer under the Management folder.
You can close all the connections prior to your restore, but more than likely SQL Agent is reconnecting immediately after you kill it.
Try restoring your database via T-SQL:
Use Master
Alter Database [database_name]
SET SINGLE_USER With ROLLBACK IMMEDIATE
RESTORE DATABASE [database_name] FROM DISK = 'E:\backup\zreports.bak' --location of .bak file
WITH REPLACE
GO
Good luck!
Chris Powell
George: You're kidding.
Elroy: Nope.
George: Then lie to me and say you're kidding.