Mid 2005 iBook Trackpad intermittent w/ Leopard

[lorkp]

I just installed Leopard onto a stock Mid 2005 iBook. However, after restarting, the trackpad doesn't work sometimes. The weird part is that if I hold down the option key while loading, I can move the mouse around in the boot selector screen. When the computer loads though, it still won't work. I got it to work again after the first episode (I don't know how I did), but it's doing it again and I can't seem to fix it. It seems to be a software issue? I've reset the PRAM and the PMU. Any other ideas? It's running 10.5.6