Actually this is fixed now, but I thought I'd post the situation.
I recently lost a Windows 2000 profile to corruption so I had to build a new one. I managed to copy most stuff from the old profile like documents etc but of course most app settings were lost.
Another thing that was apparently lost was TrackIR3 functionality in MS2004, I have no idea why as IL2 AEP was not affected. I decided I might as well download the latest drivers & install them, try & fix the problem by essentially reinstalling the thing.
After installing to 3.12 I got the couldn't connect to hardware thing (which might be part of the sticky thread at the top of this forum I don't know, I haven't read all the way through it) so I highlighted the yellowed out item in the USB tree in System Hardware window and on Properties selected to find/update driver. I deselected all location options & the driver was found & applied.
All back to normal now. But I'd like to know what happened to the MS2004 functionality, and how to reapply it without having to reinstall the TrackIR if it ever happens again...