Tech support for old grandmothers does not belong in this thread.
But anyway, you first check, and double-check that your computer has all the cables attached, back in the day people called it wires, look for those, they are many all should be attached. Also tell your dog to stop running around your computer when you are trying to computer.
I know that you are not interested in helping me because you will lose then, I hope someone else will help...