Screen flickers due to unknown hardware problems.
Cause:
The video data cable may be poorly shielded or an older interlaced display unit (new technology uses non-interlaced) is being used. These situations can contribute to excessive eye strain and headaches after prolonged use.
Solution:
Refer to next-level support or a qualified computer technician for possible replacement of video cable (wired into display unit) or upgrading display unit and video card.
For a temporary workaround, try the following in sequence:
1) Adjust or shift the display unit slightly.
2) Move the display unit to other side of desk and a different angle.
3) Move the computer and display unit across the room, or to another room away from fluorescent lights, laser printer, power lines in wall, or another device.