No Display on Startup

piedude

Honorable
Jan 6, 2014
9
0
10,510
So, out of the clear blue, my moms pre-built PC wouldn't show anything on the display on startup. I did the first thing anyone would do, which is unplug and re plug everything. Next, I switched monitors, and concluded that the monitor was not the problem, as that monitor wasn't working either. then I opened it up, took a brush, and flicked away all of the dust from the heatsink, power supply, gpu, and all the dust I saw. Then I tried it again, this time with an hdmi cord and dvi cord, and neither worked. This prebuilt has a dedicated gpu along with onboard graphics.

CPU: AMD A8, unsure of exact model
GPU - Asus, but there is no model #, and I can't get more info on it since I cant see any image with it, it has a fanless heatsink, a displayport, vga, and dvi ports in the gpu, but no hdmi. The hdmi port was in the mobo.
mobo- No info
Case - Asus Essentio

Any help would kindly be appreciated. There is something in the gpu and onboard graphics, and idk what could be affecting all visuals coming from the computer. Tanks!