Im not sure if this will help but its a longshot.
When I reinstalled WinXP. SP1a was the first thing I installed, then I downloaded the USB2.0 patch from Windows Update, then I installed SP2. After that, I went to Device Manage, updated the High Speed USB Devices and then USB2.0 worked straight away without restarting.
I never used any other software from my USB2.0 PCI card. Just the Microsoft stuff.