HP 5200C scanjet using USB only work in XP. Drivers are down-loadable at HP web site. The HP driver (sj662en,exe (ver 2.02 2001-12-12) has error. Must use SJ630en.exe to update the USB firmware. However, this pieces of HP software cannot run in Vista (this operating system is not supported) nor Win 7.
So, the lesson is NOT to rely on HP for drivers. Good lesson when you shop for future stuff.