Some network cards have a feature known as "Wake-on-LAN" (WoL) which allows a person to remotely turn a computer on. Some other devices have similar features, and my guess would be your firewire board is one of them.

You might want to consider upgrading to SP2 (for reasons that have nothing to do with your current problem), as well as checking for any updated drivers. Use Google to see if other people have the same problem as you, and what they might have done to solve it. Contact the company that made the board, and ask them if they've heard of the problem and maybe have a solution stored away somewhere.

You have to do more than just fumble around hoping you'll find the answer. You've got all kinds of resources available to you, but the answer just isn't going to leap out at you from them unless you at least look first.