Monitor Screen causing faint 'beeping' on external soundcard.

I have an ASUS VS248 Monitor that seems to be producing a faint beeping sound in my headphones when I have the monitor turned on. When I turn the monitor (only) off, the beeping mostly stops. So I'm fairly sure it's got something to do with interference from the monitor.

I have a PreSonus Audiobox USB external soundcard that I use with KRK Rokit 5 speakers. The beeping sound may also be coming through the speakers, however I can only notice it through my headphones (due to the noise cancellation of the headphones). I can't really seem to notice the beeping while listening to music, but at times when I have no sound coming from the headphones, it becomes quite annoying.

The beeping sound is a faint low pitched sound (square wave type sound) followed by a slightly higher pitched beep (of the same sound) 5-6 seconds later. This process repeats. Sometimes the beeping will be rapid (BEEP BEEP BEEP).

I have tried the following without any luck of finding a solution:
- moving the USB cable (going from the audiobox to the back of the PC) away from the monitor and monitor cables
- moving the actual soundcard (box) away from the monitor itself
- removing my wireless keyboard and mouse usb from the back of my computer
- removing the microphone and audio inputs/outputs from the sound options in 'devices'
- plugging the monitor into a different power point
- changing the brightness and contrast of the monitor
- changing from HDMI to DVI monitor input
- removing the wireless adapter at the back of the PC
- changing the usb ports used for the external sound card

Anyone have any ideas? Thanks in advance.

I have the KRK 5 speakers and this beeping is driving me crazy. How do you know its the monitor interference? I feel like its coming from the speaker. Could it be some kind of setting in the DAW? Did you figure this out? I know it was a long time ago. I know these speakers kind of go to sleep if the sound is on low, could that beeping be some kind of test beeping to see if its on? Were you able to find a solution to this? Thanks!

The problem seemed to go away on its own, I don't really notice it anymore. Sorry I can't help