I kept having problems with my N8 after getting the update and now the screen is completely black, no clock nothing apart from the button in the bottom left hand corner is still lit up. I've tried turnig it off, trying the screen lock on the side, pressing the lit up button as well nothings working! pressing and holding the power button down for a while. help me!
I had this happen to my N8 - I read that quite a lot of N8s are famous for just dying like that and never waking up again. I know you said you've tried the side lockbutton, but how long did you hold it down for? I held it down for close to 5mins and it did some kind of reset and pinged back to life. Worth a try if its still not working - Good luck