Based on your description, I recommend you updating the bios in your system and uninstalling the current driver and install the latest graphics driver for your computer. I can provide the direct download link but I am afraid I do not know what the graphics controller is in your system. You can search for the driver at the following link:
Besides the above, I recommend you installing the monitor drivers and also checking the monitor settings. Make sure you use a direct connection (no video adapter) between the monitor and the computer since this can affect the image.