I recently purchased a DELL Venue pro 8 and my best friend OD that nite We were going to go thru reset & pasword next day over coffee. I'm not savy with these things, def smarter she threw ou manuals

(reboot)shut off and turn on to see if you still get message

Dell Venue 8 Pro frequently drops WIFI and bluetooth

Venue 8 Pro WiFi and Bluetooth issues

When you think you can bypass the password why then install one? In the worst case you could try to reset it to factory settings, but then you will lose all data on it. If you have a good recent backup I would advice to do that.

Reboot the entire system clear the virus

See this... http://hard-resets.com/dell-venue-pro-hard-reset/

Seems to be a common problem.
You are on the right track with holding down power button.

1. Hold down for 20 secs, Wait 5secs, hold down for up to 10 secs, it may turn on before then.

2. Does the screen have a dim glow, even though there is nothing on it?
Let it discharge itself so the glow is gone, may take some hours.
Plug it into charge for at least 30 mins.
Try to turn it on.

More info here
http://answers.microsoft.com/en-us/windows/forum/windows8_1-performance/why-wont-my-dell-venue-8-pro-windows-tablet-turn/50573983-8cb7-4770-bf5c-478e63ec5cf8

vickie,
To delete an app off your tablet you can hold your finger on the app and a bar will pop up at the bottom of the screen with the option to uninstall the app.
Thank You,
Dell-Jesse L
Dell Social Media and Communites

"right click" by touching and holding on them until a square appears - you'll find the "delete" option in the list that opens.

Check to make sure that the keyboard is fully charged.

Make certain that you have the camera app installed and linked to the start screen. You'll find it in the app list.