Yesterday the cursor disappeared so I turned the pc off manually. When I turned it back on after a few seconds all was OK. Cursor disappeared again, so I tried the same thing, but the computer now won't turn back on at all.
The start button lights up amber then immediately goes out. No sounds. I have unplugged and plugged back in all the cords from wall, router, modem. The lights on modem and router are all normal, The laptop I am using as I type right now is hooked up to the exact same system, I'm not using the laptop wirelessly. I have also unplugged the power and held down the start button for 10 seconds as was suggested on Dell's website. But pc still won't respond. If I unplug and replug the whole thing from the wall or plug and replug the AC adapter, I see the Dell logo for a moment on the screen and then the message it is going to power saving mode, then black.
The pc that won't turn on is a Dell 8900 which I bought 6 months ago and has worked perfectly up to now. I use Windows10.