First what version of Win7 are you running?
If you can see UxSms in the Task Manager/Services Tab: Right click on it there and select Start Service
or, type services into the Start Menu search box, select services, then find Desktop Window Manager . Right click on it and select properties. You can start the service from here.
To post a ss, you need to upload it to a hosting site like ImageShack or Photobucket, copy the direct link and paste it into the box that appears when you click on the small tree icon (second row, top of reply box)
Did you try Neil's suggestion? Open WB config and select Windows Aero, apply changes, then reboot. Do you have transparency then?
If no, the problem isn't WB's. If yes, reapply a WB and see if it still works.