After charging my Samsung GT 7.7, I switched it on but it just showed the "Samsung Galaxy Tab 7.7" and stayed like that like it hung.
What do I do?
If it has a removable battery, remove the battery, put it back and run it. Else wait for it to discharge then charge and turn it back on. If none of these solve your problem, boot to the Recovery Menu and factory reset your device.
Samsung devices have Download and Recovery modes with buttons combo to enter them. I don't know what it is for your tab, but usually for Samsung devices it's vol up + home button + power button. Make sure the device is off before doing so.
Once you enter Recovery, just factory reset the device. As long as it's bootable, this could make it work.