PLEASE PLEASE HELP

I have just got my N900 back from repair at Nokia and apparently it was checked and working.

My Nokia orange light stays on and the NOKIA sign in the background stays visible and the text says installing software update and this stays at 4 %. I cannot turn my n900 on and i am desperate. It is only 8 months old and until today i was very satisfied with it and the performanance but now am feeling very disappointed and p....d off. Am i doing something wrong and is there something i can do to rectify this.

it will not work no matter if it is connected by USB to pc, laptop, wall socket or car socket.

PLEASE PLEASE HELP ME KEEP MY CONFIDENCE IN NOKIA AND MY UNIT and HELP ME RESOLVE THIS PROBLEM ......

THANKS GUYS