Computer repaired, now monitor and keyboard won't work

My computer had to get some work done on it because it was freezing on the welcome screen due to it being out of RAM. The tech cleaned it up and put about 105GB of files on an external; he said the computer was now starting up and running smoothly. Well I plug everything back in, turn it on and it powers up fine but the monitor is saying "no signal" and the keyboard is not lighting up at all. There was nothing wrong with either up until now (monitor's pins on the plug are not bent, connection is secure and the usb plug and port for the keyboard are fine) I thought maybe something got knocked loose on its transport home, so I inspected the inside- nothing was loose and everything appeared secure. All three fans are running as well. So next I popped out the CMOS, let it sit for half an hour and put it back in. Same thing- no signal on the monitor and no lights on the keyboard. A friend suggested I perform a hardware reset but I have no clue how to because my computer is 6 years old and all the tutorials I've found on how to do a factory reset are written for newer models and I can't find the same labels on my motherboard. Anyone have any idea what might be going on and how I could fix this?? The OS is Windows 7 64 bit and it's running on a Compaq cq4010f with an AMD Sempron LE-1300 cpu. Thank you so much for any help!!