When i turn my computer on its just a black screen and the monitor says entering power saving mode and the monitor light just blinks. The power button light on the tower is on, the vga cable is not broken i tried it on other pcs, and the monitor is working fine. The tower is a dell optiplex 980. The issue started happing when i took out my gtx 1050 ti gpu from it and put it in a different pc ever since that it would just be a black screen please someone help.