Thanks for posting in the Slingbox Answers Forum! I'm sorry to hear you are experiencing video resolution issues when connecting to your Slingbox PRO-HD on your computer.
This issue is usually related to the computer you are connecting to the Slingbox from. I have seen in other forum posts that a resolution is to update the NVIDIA Driver on your computer. You can verify this is an issue with your computer by connecting from any other device.
Below is a link to a thread from the forums that shows this has worked for other users:
Hope this helps!
The Sling Moderation Team