UPDATE - Please note that the updated post on this topic is here. So if following method does not work for you, please refer to the new tutorial.
WARNING: Phone flashing is a double-edged sword; it may be useful and dangerous at the same time. It may brick/damage your phone for good if not done carefully, so please DO NOT flash your device if you don’t know what the hell flashing a phone means. Also backup your phone data before flashing as everything will be deleted during the process. I am not responsible if anything goes wrong!
In this post I will explain the use of Phoenix Service Software to flash Nokia mobiles (normal flashing when the phone is in working condition). Flashing means re-installing phone’s firmware (Operating system)