Without looking at the laptop or knowing your specific issue, it's impossible to tell if it's worth fixing one way or the other. In my opinion, it'd be worth the $39.99 to get Future Shop's technicians to diagnose the unit, determine what the issue is and see if it's worth fixing from there.
If you're absolutely sure that your motherboard needs to be repaired or replaced, you'll likely want to look at a new laptop. It may be difficult to find a replacement motherboard for a laptop that's six years old, not to mention the price of the part and the labor. Then there's the fact the laptop is six years old -- a new one will very likely outperform your old one in every way, and every part will be warrantied for the full manufacturer's warranty, and not just a replaced motherboard.
Hope that helps!
