My monitor has a strange behavior but I think it is a problem of VGA: when you reactivate after screen saver (with a click or a keystroke), rather than display the last screen, appearing in succession, a white screen, then black, then red (orange), green and blue; and it is repeated indefinitely; (the same thing happens when you turn on the monitor with the PC turned off). The only way out of this problem is to restart your PC with the appropriate button. It is as if the card he falls asleep. Thank you. - VGA card: AMD Radeon HD5450 SL (Branded ASUS); win7; monitor Samsung LS24F356FHUXEN - power option: turn off the display> 10m - Put the Computer to sleep> never.
It could be a bug in the drivers, but as the HD5xxx series has been moved to legacy status, there are no further driver updates available.
The latest Crimson driver for your system is 16.2.1 and is available here.
The last Catalyst driver for your system is 15.11.1 Beta and is available here.
I would recommend using DDU to sweep your system of AMD drivers, and then trying the drivers above to see if they resolve your issue.