Does it shut off completely? or does it remain on, displaying a blank white screen?

A blank white screen could be the notorious WSOD (White Screen Of Death), for which there is no known fix. However, WSOD rarely happens these days - it seems that only a certain number of 770's were susceptible to this failure, and they have mostly failed and been thrown away long ago.

If the screen shuts off completely, there is more hope for your 770.

You mention problems with charging, but you say that the battery is OK. Has someone tested the voltage and found that it has a full charge, or what? You will need a full battery before you can do anything else.

Have you tried removing the memory card before turning on the 770? Data corruption can happen any time and can lead to any number of weird effects.

If it still won't turn on, the next thing to try is to reflash. Have you done this? The procedure to use depends on whether your desktop computer uses Windows, Mac or Linux. You have to start with the 770 turned off, the memory card removed, and the battery full.

Assuming that you use Windows, you need to download and install (on your PC) the Nokia Internet Tablet Software Update Wizard, which you can get from here: http://europe.nokia.com/support/prod...ftware-upgrade .

After you have installed the Wizard on your PC, you can use it to automatically download and install the OS2006 operating system on your 770. Other operating systems are available from http://tablets-dev.nokia.com/nokia_770.php if you are interested in trying them.

Unfortunately, it has become difficult to find much help for the 770 on the wiki page at http://wiki.maemo.org/Updating_the_tablet_firmware. Links for the 770 are still there, but they are hard to find amid the great mass of material for the N900.