Thanks for posting in the answers forums! I'm sorry to hear you are getting poor video quality when connecting to your Slingbox PRO-HD on your PC. Have your tried connecting to your Slingbox on any other devices to see if the issue happens when connecting from any device? As it may be only related to the PC you are using.
Also, could you try changing the quality of the video to see if the issue persists when using any quality?
Have a great day!
The Sling Moderation Team