Dell WIN10 DESKTOP (NOT LAPTOP!) does not wake from sleep

Dell WIN10 DESKTOP (NOT LAPTOP!) does not wake from sleep.

After frustration with sleep issues, PC was set to never sleep and hibernation was DISABLED, hybrid sleep was set to OFF.

PC went into sleep overnight, and cannot be waked.

After manual shutdown & holding for 45 seconds, PC goes immediately back into sleep mode on pressing start button, with light flashing but will not wake up. No opportunity to get control of the PC.

USB wire-connected keyboard & mouse are not "on" and thus not recognized by sleeping system.

IE, NO WAY TO GET COMMAND PROMPT or GET CONTROL OF BOOT or SYSTEM, SO CANNOT TRY THE MANY TIPS FOUND IN FORUMS FOR ENDLESS SLEEP MODE, NOR CAN I UPDATE DRIVERS - sorry for CAPs but I've seen many suggestions, all of which rely on being able to access the BIOS or Safe Start etc, so are not helpful to this case. Thanks in advance for any help!

Thanks mQ573 --

Disconnected PC power cord and let machine sit for an hour. Re-connected power. Now, PC start button will not do anything. No beeps, no lights, no boot. Machine is inert. So, good news is PC is not in perpetual sleep. Bad news is machine is dead. Will investigate how to replace CMOS battery when I get time. TY for your help.

That's what I was suspecting from the start.

Don't even bother with the CMOS battery. You probably have a dead Power Supply Unit. It can be tested but not over the net .

You can have it replaced or DIY (a bit harder than the battery). Make a note of the form factor and the wattage. Get a good one of a slightly superior wattage. FYI, about 26% of failures are due to old/dirty/cheap PSUs.

You may also elect to buy another machine and probably connect your present HDD to it (Internally or externally).

Good luck.

Many thx! We have other systems, plus I decided to get an HP refurbed Win 7 pro 8 gig while they are still available, and that one is the replacement for the done Dell, so no panic. Will learn about PSU replace, but I'm software, not hardware, so who knows. Really appreciate your advice.