Just throwing it out there in case this helps somebodies search. I just bought one of these old Hitachi PI-500 starboard tablet monitors and had a heck of a time finding drivers that worked with Win7-64bit. But found them at thepandacity.com for the Yinova tablets they sell. This is the driver, 20110308_Driver V4.12.exe. I was lucky and recognized the pen it uses, same tech has obviously been licensed a LOT!
Still not as good as a Wacom Cintiq that I took to work. But better than not having anything at home to draw on!!! :0