Acer Altos R5250 Series User Manual page 113

If you are using an add-in video controller card, do the following:
1 Verify that the display monitor works using the onboard video
controller.
2 Verify that the add-in video controller card is fully seated in its slot.
3 Reboot the system for the changes to take effect.
4 If there are still no characters on the screen after you reboot the
system, reboot it again.
Take note of the beep codes emitted during POST. This
information may be required if you seek technical assistance.
If POST does not emit any beep code and characters still does not
appear, the display monitor or the video controller may be
defective. Contact your local Acer representative or authorized
dealer for technical assistance.
95