If i fail to upgrade my n73 to N73 ME,my phone will die?

It can happen, yes. I had it happen twice before it worked and i had to send the phones back to Orange. The third time it worked.

I think, however, there was something on my PC that had tripped up the update. The third time i had a fresh boot of XP running and it went right on, no problem.

From reading the Symbian/N73/3G forums, i'd say about 3-5% of people who upgrade the software "brick" (kill) their phone. Which means you have about a 95-97% chance of it going through.

Its your choice.

Thx Jeeper 4 replying....i am on orange too ,hope it wont destroy my phone...cos i payed a lot of money on it