This should be a picture of your Motherboard. Make sure of the connections marked. Make sure they are fully seated. Please put 1 stick of ram in the top yellow slot. Only put 1 stick in. Unplug/turn off the power supply. Press the power button until the led lights go off or for 30 seconds to drain all power from the board. Remove the battery marked with a green circle. Take not of how it was installed. I may even go so far as to buy a new one. It is usually a model CR2032 and can easily be found at any computer store or watchmakers shop. They are really cheap. If you buy a new one, take the old one out before you leave to go get it. Remove the battery and leave it out for at least 20 minutes. Then replace it and turn on the power again.
With nothing connected other than the connections shown, 1 stick of ram and the CPU, keyboard and mouse. Try to start the computer. If you go into bios, please set optimized defaults, set the correct date and time, find all the info I asked about before, save and exit.
The second image is of the CLR RTC connection. Make sure this is in the normal position before starting any of this.
If you have any questions, please ask.