When upgrading to windows 10 you will often need to upgrade your drivers as well . Have you done the updates for windows 10 yet or just the install. If not go to your windows updates and run the updates till your up to date completely . If this brings no joy then go into the device manager and find the display adapter. Does it tell you what your display adapter is or does it say generic. If it says generic go to HP support enter your laptop model and look for the proper driver for your display adaptor, download it and install. You may also want to check your other drivers to make sure they are up to date with the windows change. Hope this helps