Try turning off the laptop, connecting an external monitor, turn on the external monitor and then turn on the laptop. Can you see fine on the external monitor or do you have the same problem?
If you can see fine on the external monitor, you may need to remove and reinstall the drivers for the connected display. They may have been messed with when you did the uninstall of the application.
If you can't see on the external monitor either, then your graphics card may be needing replacement.