There are stripes on the monitor, what's the problem?

Question

Monitors

Answer 1

If there is no ground feedback (disconnect the third pins of the power cords), then it means a bad video card, if the bands are narrow and chaotic, or a bad power supply, if the bands are wide and fast running.
Connect the monitor to the computer via DVI, if any. If not, try a d-sub cable with ferrite barrels if you're having the same problem without them.

Answer 2

The problem seems to be in pickups, check via a digital channel, if it is not possible to try changing the cable, remove strong sources of radiation nearby, hit.