I've had my N900 on Vodafone UK for about a month now.

This evening I discovered it had turned itself off, and it won't reboot.

I get the Nokia logo backlit, and the indicator light illuminates. I get five flashing dots, the indicator light illuminates again, then fades. The screen goes dark.

Any clues what I need to do?

Sorted now!

Amazing what a difference plugging it into a charger makes...

clean the sim card and put it back in. This may be the N900 drained all of your battery and then you are trying to turn it back on while the battery is still too low. Try using someone else full charge battery from Nokia 5800 or use Nokia 5800 to charge your current battery then try it again.

Try desktop charger for the battery, Nokia N900 will refusing to charge if your battery is beyond it's low point of recognition by the device.

This is may be hardware limitation of the N900 or may Software not so sure but more like hardware.


Edit: LOL

I have to admit, my N900 normally manages fine overnight but it has caught me out a few times where it unexpectedly drained a full battery overnight.

If you leave the wrong thing open, especially web pages or widgets which update themselves, or just ran something the previous day that is from devel and "not quite there yet", then you can find it empty when you least expect it.

I usually close all applications and stick it on a desktop with no widgets on it that auto update, when I leave it overnight now. There are also known problems, not sure if they are fixed now or not, with if you have video files on there that it doesn't like then the tracker that updates your media library periodically can get stuck and max out the CPU which will result in a dead battery. That will seem random as you never really know when it will next do a probe to see if you added anything new.

I'm not saying any of these were the problem, but it sounded like you suddenly unexpected had a dead battery overnight and these are mostly simple things to watch out for to avoid it happening again. I have had exactly the same issues on desktop PC leaving web browsers open for days, its just when it happens on desktop PC you just use more electricity and your CPU fan speeds up, on your phone however its dead battery time so you have to be more careful. I know the N900 is the first device where the web browser is usable enough to keep it open for long periods, so its the first time its ever been an issue for me. I would never dare leave it open on Windows Mobile.