Screen flickers due to low vertical refresh rate.
Cause:
The monitor Hertz settings are too low. The screen is not being repainted frequently enough. This will cause flicker and low refresh rates.
Solution:
Increase the number in the display 'Settings' in 'Control Panel', 'Display'.
1) Click the 'Start' button to display the 'Start' menu.
2) Select 'Settings', and select 'Control Panel'. (The 'Control Panel' window appears.)
'Control Panel'
3) Double-click the 'Display' icon. (The 'Display Properties' dialog box appears.)
'Display' icon
4) Click the 'Settings' tab. (The 'Settings' tabbed page appears.)
5) Click 'Change Display Type...'. (The 'Change Display Type' dialog box appears.)
'Change Display Type...'
6) Click 'Change...' in the 'Monitor Type' group.
'Change...'
7) Select a higher refresh rate. (The refresh rate is indicated by the number followed by 'Hz'.)
NOTE: At least 70 Hertz at 800x600 resolution is recommended.
8) Click 'Apply'. (A 'Systems Setting Change' dialog box appears, prompting whether to restart the computer. The computer must be restarted for the settings to take effect.)
9) Click 'Yes' to enable settings immediately.
