I have this issue to my lumia 800, yesterday morning has gone off and it won't open.
I tryed different things like reset , and all the buttons combinations but it doesn't work, i also tryed warm it, still doesn't work.
I hope someone could help me.
i am having the same problem. I "solved" this, using the following trick:
-take out your sim card
-charge the phone about 30 minutes directly with original charger and cable
-unplug the cable
-hold button about 10 seconds, then try turn it on
-as soon, as you see NOKIA plug in charger
later you can turn it off and on to put in your sim card.
That's my standard procedure since last update. But now I am having a new problem: new update is not working, so I guess they messed up the bootloader (trick with powerbutton and camera button is not working).
Can anybody confirm this?