[Uprising]

Once you install the demo, it should be in your "My Games" list in your STEAM account. I would exit out of STEAM and restart it.

Go to the My Games tab/list and you should see the Demo. It's either installing or done. If it's done, high-light it and click launch.


You can also try going to Task Manager via hitting ctrl-alt-delete and finding the STEAM process and ending it if you feel comfortable doing that?