Galaxy p1000 is frozen cant switch off nothing is happening

Hope this helps:

How to Hard Reset Samsung GT-P1000 Galaxy TAB:
If your Samsung GT-P1000 Galaxy TAB is frozen and unresponsive, press and hold [POWER ] for 8-10 seconds. The device will reboot automatically.
If this does not solve the problem, perform a factory data reset. In Menu
mode, select Settings ? Privacy ? Factory data reset ? Reset phone ? Erase everything.




Hard Reset Samsung GT-P1000 Galaxy TAB with keys With the Samsung Galaxy TAB turned off, press and hold the VOLUME DOWN button, and then briefly press the POWER button.

Here is more:

Check these Three Options: Re-Partition Auto Reboot F.Reset Time.
Select PIT file in its field.Put Device Into Download Mode ( Press Volume Down Power ).
Connect Cable To Phone.Make sure ID:COM box highlighted yellow that the device is connected to the PC.
Start Downloading PIT file by clicking Start Button. Then wait for "Pass" to be appear on the screen.
Click on Reset button, then unselect Re-Partition box. Then select PDA, PHONE and CSC Files each in his field.
Put Device into Download Mode again, then connect to the PC.
Start Downloading PDA, PHONE and CSC files by clicking Start Button. Then wait for "Pass" to be appear on the screen.
After all is done reboot the phone and Do Full Reset: *2767*3855#.