I have an Acer Aspire M3300. So today I recieved a ThermalTake 850w psu and a Diamond Radeon 6870. I installed the new things with no problem, but not the display will not work and my keyboard will not work. (USB). I have both 6 pin connectors connected to the 6870, the 24 pin and 4 pin connected to the motherboard. The hard drives are connected. Every fan in the case works, including the graphics card's fan. The only connector I left was a 4 pin connector that comes from the front of the case, I'm pretty sure its for the micro SD slots.
Any clue on what I did wrong?
Did you delete the old GPU in device manager before shutting down to install the new one?
I just tried putting the old one in, but the display still won't work.