Couple things to add.
There are actually 3 different Sidewinder Precision Pro's. There is the
gameport only version, a later release of the gameport one that also came
with a gameport to USB dongle that could be plugged into a USB port, and the
Precision Pro 2 which is USB only.
If you have the first one then it will never work on USB, even if you manage
to get one of the gameport to USB dongles that came with the second type.
If you have the gameport version that came with a dongle then you should be
able to get basic use out of it by just plugging it in. You won't be able to
get any of the key mapping abilities for the first two devices as the
Profiler software won't run on an NT OS.
If you have the USB only, the drivers are built in the operating system. You
will have to install the Profiler software from the CD that came with the
device.
If that doesn't fix things then you should check to see if your motherboard
is using a VIA USB controller. If it is there are some updates that fix VIA
chipset USB controller issue.