Trojan Horse Fontal.A causing the Symbian phome to fail at next reboot
Fontal.A is a SIS file trojan that installs a corrupted file which causes phone to fail at reboot. If user tries to reboot the infected phone, it will be permanently stuck on the reboot, and cannot be used before disinfecting.
The Fontal.A is a trojan, and as such it does not spread by itself, not over bluetooth or any other channel. Most likely way to user to get infected would be to get the file from IRC or Peer to Peer fileshare and install it to the phone. So to avoid Fontal and other trojans, download files only from legal sources.
Follow the instruction on how to disinfect the said trojan by visiting http://www.f-secure.com/v-descs/fontal_a.shtml