If an NC just appears to be dead when you try to switch it on try the following. First make sure that the LCD contrast control hasn't just been turned right down (though you should still have heard it beep if it was alive). Next make sure that it has fresh batteries fitted or, perhaps better yet, try running it from the external mains adaptor (aka PSU).

If neither of the above fix the problem then it's possible there may be some sort of software lock up. There are two resets you can perform to try and kick it back into life if this is what's happened. The "soft" reset is quite "tame" but may get it going, however some of your settings may have been set back to defaults but your files should remain intact. To do this turn the NC on while holding down the [Function] and [Stop] keys. You should hear a high pitched beep if it is successfully woken up by this.

If a "soft" reset doesn't work then there is a more "fierce" reset that you can try - the "hard" reset is performed by switching on while the [Function], [Stop] AND [<-Del] keys are all held down. This will rease all files in the machine and, if successful, a very low pitched beep will be heard as the machine switches on and you'll be taken into the time/date setting screens just like when the NC was first bought. An alternative to performing a hard reset using those keys is simply to remove all the batteries from the NC and leave it for a long time (preferably at least several hours). In this case you must unscrew and remove the lithium button cell as well as the main alkaline batteries. Once again, when swithcing on after such a reset a low pitched beep will be heard and the machine will be totally reset just as if it were brand new - all files will have been lost so things like the address book probably need to be restored from a copy on your PC.