There is no virus that works on a BlackBerry. However, it is possible to get a worm on your media card (just like on a usb flash drive) that can infect your computer and vice-versa.
If you have a media card in your BlackBerry, and if you connect your BlackBerry to your computer with the usb connector, the worm could get transferred from one to the other. Nothing can cause your BlackBerry to send mass email, but a worm can do that on your computer.
If you do connect your device to your PC and it has a media card, have your antivirus scan the card.
I think what happened is your computer is infected and causing all the trouble. There are viruses and worms that aren't always detected by antivirus software. Try an online scan of your computer with a different antivrus such as the ESET Online Scanner, which has one of the best dectection rates. Free ESET Online Antivirus Scanner
You might also download the trial of Kaspersky Antivirus and install it on your PC. It's good for a month and has great detections. Free Kaspersky Anti-Virus Software 2010 - Kaspersky Lab United States
(I don't work for either of these companies, but I know they are good products).
You could also go to a free computer help forum and get help to check your computer for undetected viruses. Virus & Other Malware Removal - Tech Support Guy Forums MalWare Removal; View forum - Malware Removal
It's possible you have a worm that is infecting your entire home network also. http://www.securelist.com/en/glossar...gloss189275916