No more startup beeps, and screen in power save mode

Shurewalker

Yesterday I unplugged the computer to turn it off (why I don't know) and now when I turn it on, screens stays in power save mode, there are no more start up beeps, and I don't see any light on the motherboard (Acer D1F-AD) not sure if it has one. Somebody please help, the computer is not even mine! I have tried the obvious, unplugging then replugging back in, restarting, checking all concections to make sure they are secure, cleaning the contacts on the memory, switching memory slots,. I just don't know. I did take out the memory then powered it on to see what would happen, and right away, one long, loud continous beep.
Thankyou