Try this 1
1) 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 devmgmt.msc and
press Enter. "Device Manager" will be opened.
Expand "Display adapters" --> Under the "Display adapter", right-click on your
display adapter (Example : Display adapter may be Nvidia or VIA etc ) -->
Select the option "Uninstall" --> Restart your laptop.
2) 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.