Hi,
Thank you for writing to Microsoft Community Forums
We understand your concern as you are unable play the game in full screen. In order to get clarity and to assist you accordingly, please reply with the answers to the questions below.
- What is the Windows 10 Version and Build installed? (Type winver in Windows search/Run command)
- What is the model number of the HP PC?
- Are you aware of any recent changes on the PC prior to this issue?
- What happens when you try to open any game in complete full screen mode?
We would suggest you to refer the steps as mentioned in this article: Fix problems with apps from Microsoft Store
Also, suggest you to updated the display driver from Device Manager of the PC, please refer this article: Update drivers in Windows 10
Regards,
Aditya Roy
Microsoft Community – Moderator