Quick guide to get into the service menu on C series, but beware that there are options in this menu that\'ll brick your expensive toy.
Take the battery out, and remove the mains power. Hold down the D and M keys and put the battery back in, hold this for about 2 seconds and the service menu will come up. Attach mains at this point if you\'re concerned your battery won\'t last.
You don\'t need to worry about locking the battery cover, it will work either way (unlike the Flashing menu which requires it to be locked).
I stress you to be careful, I\'ve already bricked my C760 once but I was lucky to be able to do a NAND Flash Restore.