Desktop doesn't display and won't turn off

[helenelliott]

Running Windows 10 and using a tv as a monitor via hdmi.

So a few days ago my desktop was in sleep mode but would not turn on. After trying a few things, I just held down the power button to shut it down completely, but it wouldn't work. Restart button didn't work either, so I hesitantly flipped the power switch to turn it off, but then it wouldn't turn on. As I was checking inside to verify the green light on the motherboard was on to be sure it was receiving power (it was), it turned on on it's own somehow and worked fine. Weird.

However, next time I trying turning it on (from completely off) it wasn't turning on. I flipped the power switch off and on and tried again, and it turned on (fans started and computer lights came on) but would not display (the tv works just fine when connected to my laptop), just like the first time it was in sleep mode but wouldn't come on. I noticed that my key boards lights don't come on, and the computer doesn't make any sounds when I unplug things.

Any thoughts? Could it be the power supply is faulty and not giving full power? Or something worse?

Thank you for your help in advance.

 

[Cycloid Torus]

You may have the right idea - PSU - or, perhaps, power switch (yah, they go bad). Could be last new thing you added. Or a bad connection (or two). Could even be video card or a bad driver. Sleep mode can be quirky as well. And RAM too.

First, confirm you have a good backup of your data.

When that is done, get manual for the motherboard and the video card and check all the connections to make sure they are 'well connected' and that all accessories (keyboard, mouse, printer, scanner, etc) are fully connected - and see if the problem is gone.

If not, I would review this artlcle https://www.computerhope.com/issues/ch000312.htm and organize an approach to easiest==>hardest steps.

To test power switch, try removing power switch from motherboard and shorting the power connection pins by a brief connection using a small screwdriver to see if it starts properly