1. Shut down your computer, then unplug you UPS, bypass and it and leave it off. Reconnect to AC power direct and power up. Is it still shaking?
If so then:
2. Checking (and Changing) the Refresh Rate in your PC:
Resolution
Note: Some display adapters have proprietary software that may require additional steps.
“Start” -> “Settings” -> “Control Panel” -> “Display” -> “Settings”
The “Desktop Area” contains a horizontal scroll bar that is used to adjust the resolution. Point and click on the scroll bar to change the setting, try a lower res 1st, 600×800.
Click “Apply”
A message appears stating that “Windows will now adjust your display settings.”
Click “OK”
The display flickers for a moment and reappears in the new resolution.
NOTE: Some computers may require you to restart the computer for the new resolution setting to change.
A message appears asking you “Do you what to keep this setting?”
Click “YES”
Is it still shaking?
Then try this:
Refresh Rate
Start Menu -> Settings -> Control Panel
Click on the icon “DISPLAY”.
Click on SETTINGS tab.
Click on the button “ADVANCED”.
Click on ADAPTER tab.
Change the Refresh Rate from Optimal to ADAPTER DEFAULT or 60Hz and click apply.
If under the ADAPTER tab you do not see refresh rate, do the following:
Start Menu -> Settings -> Control Panel
Click on the icon “DISPLAY”.
Click on SETTINGS tab.
Click on the button “ADVANCED”.
Click on the MONITOR tab.
Write down the monitor type that is currently in use (so that you can change the setting back if you need to). Click “Change”. In the “Select Device” menu, click on “Show All Devices”. The device windows appears showing a list of manufacturers and a list of models. Select “(Standard monitor types)” as the manufacturer and select “Super VGA 1024×768″ for desktops and “Laptop Display Panel 1024×768″ for laptops. Click “OK” and reboot the computer if prompted.
Try different refresh rates, mine uses a refresh rate of 75mhz.
If it is still shaking after all this then have you IT guys replace the monitor.
If it stopped shaking after bypassing the UPS, contact your IT guys and have it checked or replaced.
Hope this helps.