Nokia Software Updater and Bricks
Unfortunately, Darla Mack experienced a problem with the Nokia Software Updater tool on the Nokia N73. It basically turned her phone into a nice, expensive, paperweight, otherwise known as "bricking" the phone.
Prior to the introduction of Nokia Software Updater, if you actually needed to have your phone updated, for example to solve a particularly crippling bug, the phone would have to be sent to the nearest service center. That's not practical for most end customers to do as it means being without their phone for an extended period of time. Now with Nokia Software Updater, it is possible to upgrade many Nokia handsets without having to send it away.
Unfortunately, there are some reports out there of Nokia Software Updater not working with some phones and causing the phone to be dead. In some cases, with some models, the Nokia Software Updater tool will support upgrading a "dead phone." It doesn't hurt to try and run the Nokia Software Updater tool again. If it fails, you're only choice is to call Nokia and get them to repair the phone under warranty, assuming it is. Or you can do what Darla suggests and send the phone off to some third party location to get the phone fixed. Nokia's US website has a place where you can look up the nearest authorized repair facility, which may be better than sending the phone somewhere random.