I recently started my computer and noticed that it wasn't recognizing a stick of RAM, so I took it apart, and took out a stick of RAM in an attempt to find out which one wasn't working. When I turned it back on I got this screen about the Memory being changed, and instead of letting my computer boot up, I turned it off.

I then changed out the bad memory stick for the good one I took out, and the next time I turned the computer on, the monitor, mouse, and keyboard refused to work. None of the lights on the mouse or the keyboard come on, and the monitor displays "is working properly, but no connect(or something similar to that). I checked all my connections, and nothing has worked.

Any suggestions?

Does the computer sound like it is booting up? If so, that is a good sign. Howevery, I have ran into faulty motherboards that when I installed memory it shorted the motherboard out. Later I learned there was a recall on that motherboard.

Try powering the system without any RAM modules. If the board gives any beep(s) then the board is fine. Next, take any one RAM stick and plug it into the slot and then turn the system on. If this doesn't work, then put the stick into the other slot. Keep doing this with all the slots. Then repeat the procedure with the other RAM stick. Let us know if this helps.