I have an Acer Veriton 6800 desktop. I recently heard a series of beeps coming from the tower. Opened the tower and it seemed to be coming from the CPU heatsink. Now, I have no video, and the power button does not work. When I put the power cord in, everything comes on, so power is going to the device, but I think the motherboard may be defective. Took out the RAM, cleaned it, put it backin, still nothing.