"Frequent Hang up problem in N8"

[umeshmasleka]

Hi friend,
I bought N8 in June 2011, later update the firmware to Anna from Nokia care.I found my N8 hanged up while watching an edited (made suitable for N8) song video.I thought the video might hanged up my phone due to some tecnical problem.I could not restart/reboot it by pressing power key.The screen was as it is as in song scene and no song/music sound.Meanwhile,somebody called me on phone but I could not recieve the call, the went on ringing.( In my N73 ME phone or 6630 phone if it happened, I overcame the hang up problem by taking off bateery from phone ) But in N8 that trick was not useful as we can not remove battery at home by ourself.So I went to nokia care,there they blamed on viruses (might present in the phone).They reinstall the firmware and retuned my phone back in working condition.It happened again while using camera in the phone .Again nokia care person did the same by blaming viruses.I scanned my 16 GB memory card by Norton antivirus 2012 and found no virus in it.Even I formated the card and then put it's previous data back on it.
But in all incidents, My curiosity was not satisfied by the answer given by nokia care person (Virus attack).I guessed that I installed so many apps,games( some on E and some on F).Then I updated phone firmware to Belle at my home through Nokia Ovi suite ( though nokia care person warned me not to update the firmware at home as it is not full and complete, some update files will not be there).And again my phone hanged up while just handling it.Now because of the fear of hanging up, I did not install any extra game/apps.Stayed the phone as it is as after the firmware update.This time I did not go to nokia care.I waited for the battery getting fully dischared/empty.Then I charged the phone and restart it normally.It came in working condition.Since then I use the same trick to discarged the battery in hang up situation by calling to phone,Phone went on ringing until it gets fully discharged.
NOW THE QUESTION IS " WHY THIS HANG UP PROBLEM IS HAPPENING WITH MY PHONE.WHAT IS THE RESON AND WHAT IS THE PERMANENT SOLUTION FOR IT."
SOrry for my english.I request you to read every word written by me,think upon it and then guide me properly so that I will free from this hang up problem in N8.