Windows 2K / XP and up should have all the host port drivers for FireWire built in ... Check with MicroSoft for updates, first, then check the motherboard maker for the built in port updates (or the plugin FW port card maker).
The chip set on the motherboard / plug in cards are the key: see who made your FireWire port chip set ... TI, NEC, Agere' / Lucent / VIA ... ??
Anyway, Gates and Company has had several issues about buggie Windows drivers, so getting these straight from the chip set manufacturer will often resolve a number of peculiar issues ...
"Truth is one, paths are many ... " - The Dalai Lama