I have lost the operating system on my Samsung Tablet 2.

[AC Question]

First time I pressed on/off and up sound it said downloading do not turn off. This lasted for a couple of hours but nothing downloaded. Now nothing. Original problem was system was hanging on opening Tablet screen.

 

[B. Diddy]

Welcome to Android Central! You probably pressed Power/Home/Vol Down, which is how the tablet gets into Download Mode. This mode allows you to download a new firmware ROM to the tablet via USB connection to the computer. The warning not to turn the tablet off is only if you're actively downloading a file. If you're not connected to the computer, you can power down (by pressing and holding Power and Vol Down for about 15-20 seconds). Then try booting into Recovery Mode and see if you can wipe the cache partition: http://forums.androidcentral.com/sa...ing-into-recovery-mode-galaxy-s2-s3-tab2.html