Hi yolego20,
You may try reseating the monitor cable from both ends. Another step you may try is to try another monitor with computer and see if you face the same issue with that. You may also reset the factory defaults of monitor settings. You might need to check the manual of the monitor for the instructions (for resetting to factory defaults).
One more step you may try is to try booting your computer with any CD/DVD and go to F12 menu. See if the system exhibits the same behavior.
Please share the findings.
