When you switch ON your computer, start tapping the F8 key to get Windows Advanced Options (if boot menu appears, press Esc key and keep tapping the F8 key)
Select the option Safe Mode.
When the desktop appears, click on Start > Run > Type
and press Enter.
Device Manager will be opened.
Expand Display adapters > right-click on your display adapter (Example : Display adapter may be Nvidia or VIA etc ) > select the option Uninstall > Restart your laptop.
If the problem still exists then try connecting an external monitor to your laptop. Just look for the VGA connector ( there will be a monitor symbol ) in your laptop and connect it to the external monitor then switch ON your laptop.
Note: If you failed to get the display in external monitor, then use the proper combination keys (like Fn+F5/ the function key that's having the monitor symbol on it) to toggle between your laptop screen and the external monitor.
Check if are able to get a normal screen display in the external monitor or not.