Why won't my Dell Venue 8 Pro Windows Tablet turn on?

Same problem with both the Dell Venue 8 Pro and Dell Venue 11 Pro - won't power on.  I found holding power button for 20 seconds, release and press again will start the tablet.  However we should not have to fool around starting these tablets.  WHETHER IT IS MICROSOFT OR DELL GET IT FIXED!!!   IT OCCURS SEVERAL TIMES A DAY AND IS AN ON GOING NUISANCE!!!!

I've joined the club.  Got a 'free' Venue 8 from Dell with purchase of a laptop.  My post is one year after this one.  Same problem.  Won't turn on.   Happened yesterday and somehow got it to turn on.  Now it won't again.   Good this Venue 8 was a free-bee.  I would never spend money on one!!!!

Ok, so I searched up a bunch of help articles on the Microsoft site and the Dell site, and I found an online manual for my tablet. I finally got it to turn on by pressing and holding the power button for ten seconds and then another ten seconds. Based on my research, I'm guessing that somehow I managed to shut off the screen on my tablet without turning the tablet itself off, and that I shut it down. Because when I got it to turn back on, it was like I had shut it down, where I had to sign in and everything. Whatever the cause, I'm glad I fixed it, and I hope that if anybody else has this same problem,  my question and how I fixed it will help them too. 

UPDATE: If you're still having trouble, you can try scrolling through the comments; I have posted more detailed instructions in one of the comments. :)

Worked for me. Thanks to all for help. Did not ask, just started reading. I did call Dell Support and after going through 2 people, they were transferring me to a Tablet Tech (giggle) then I waited 25 more minutes and finally just hung up the phone.

I was 4 days out of warranty, no Love from Dell on that. I will say that I have also 2 Dell laptops and I bought from QVC, both have lifetime Tech Support. I really think that is the way to go. Anywho, my Venue is all back to normal. I did rhe hold down 10 seconds, 10 seconds, then pushed again and I see DELL..........happy day

Thank you. It helped me today.

I have been dealing with this on again, off again problem for a month now.  It got to a point that holding down the "on" button did nothing AT ALL.  I finally determined that the wire from the charger that plugs into the computer has a fault in it.  I did this by plugging it into my phone (same size connection) and moving it back and forth.  My phone would show charge than not charge then charge again depending on which position it was in by bending it.  If it bends the right way, it will disconnect inside and not charge or show a charge connection (e.g. little green light on the tablet which lights up when plugged in). 

I replaced the wire by removing the usb connector side from the plug that goes into the wall.  I replaced it with a usb wire I had for my phone (one end has the usb connector and the other the one that fits into the tablet which is the same size as my phone connector).  After 3 hours the battery which was initially showing 0% charge for battery one and 3% for battery two and not charging, was now showing 100 % charge for battery one and 43% for battery 2 and showing "charging."

Prior to this I had tried my phone charger directly into the tablet and got a message from the computer saying the input into the tablet was smaller than design and would take longer than normal to charge.  Then it promptly would turn off.  So I looked at the plugin output written on phone charger which read 5 volts and 1 amp.  Then I looked at the original tablet plugin output and it read 5 volts and 2 amps.  (I needed a magnifying glass to see it.)  This is twice as much juice going into the tablet for charging.  Hence my decision to replace the usb connector in the tablet wall plug with one I knew was not broken, but still use the original wall plug supplied with the tablet.   It's been two days now and all seems to be normal. 

NOTE:  Most plugins for charging units vary in output as well as connector type/size.  So just because a connector "fits" into the unit it is being tried in, it may lack the necessary right voltage input (important) and also the right amperage input.  Low voltage and/or amps may not allow charging at all.  Higher voltage and/or amps may damage the device it is plugged into.  Just something to keep in mind.

For all you out there with these problems, just hang in there.  In short, if the little green light on the computer is on there is either sufficient battery or the tablet recognizes the charger as working to some degree.  If this light does not go on no matter what you plug into it, it may then be an internal hardware problem in the tablet that should be discussed with Dell after trying the above.   Good Luck to you all!!