Try this 1
1) Try updating the "Display drivers".
2) Check your screen resolution and also the screen refresh rate.
You can find the screen refresh rate in display properties --> "Settings"tab -->
Click on the "Advanced" button --> Click on "Monitor" tab --> Now try another
"Screen refresh rate".
Make sure that "Hide modes that this monitor cannot display" is selected]
3) If the problem still exists then
When you switch ON your laptop, keep pressing the "F8" key to get
"Windows Advanced Options"( if boot menu appears, press "Esc" key and keep
tapping the F8 key)
Select the option "Enable VGA Mode" --> Press Enter
If the problem still exists then
Connect 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.
Now check if the flickering problems exists in the external monitor or not.
If the flickering problem only exists on the laptop screen then the problem may be
coming from the inverter which is going bad.