If you find the original BontempiKeyboardSetup.exe , right-click it, go to Properties > Compatibility , and run it in Windows XP (Service Pack 3) mode.
Historically, the driver was included in a file named BontempiKeyboardSetup.exe . You may be able to find this in legacy Bontempi manual repositories or archived driver sites. Bontempi Keyboard Pm 747 Driver Download UPD
It is time to stop searching for a non-existent "Bontempi Keyboard Pm 747 Driver Download UPD." The keyboard is retro hardware that communicates via analog audio or DIN MIDI, not USB. If you find the original BontempiKeyboardSetup