I understand that you are having trouble with your Slingplayer for your PC. We do not support the Slingplayer for PC any longer. We now recommend that you go to Slingbox.com and click on Watch there. I recommend that you try this and uninstall the Slingplayer completely from your PC and see if this eliminates the issue of your computer shutting down.
Hope this Helps.
Sling Moderation Team.