Ipad 2 cant power off, or anything

Switched on our Ipad2, and says need to back up Icloud," the ipad needs to be plugged in, locked and connected to wi-fi. I have connected it to laptop, it is connected to wi-fi, but nothing happens, when press the ok button. I cant even turn Ipad off.
Only had ir about 3 weeks
Much needed help

when you connect the device to your pc do it appears in iTunes? if so should automatically tell you to make a backup!
if it is not, you can do it manually by right clicking on your iOS device to the right and click make backup. Hope i helped you! :D