Windows 8 Pro x64 x86
found/extracted working drivers for the various abandoned Acer/BenQ scanners:
310U/620U
320U/340U/620U+/640U
620UT+/640UT
1240UT/5100U
640BT/640BU
4300U/3300U
4300U/3300U
x86 / 32-bit: x86.zip http://www.mediafire.com/?7m7s13nt7j1yx7g
x64 / 64-bit: x64.zip http://www.mediafire.com/?ltunj607wk0pmoe
these driver from x86 drivers from, maybe an XP installation. just
extracted the x64 ones from a drivers.cab acquired from a 64-bit XP installation disc. Both x86 and x64 drivers are tested working in my system (Windows 7 x64 with the Acer 320U, at least.)
found/extracted working drivers for the various abandoned Acer/BenQ scanners:
310U/620U
320U/340U/620U+/640U
620UT+/640UT
1240UT/5100U
640BT/640BU
4300U/3300U
4300U/3300U
x86 / 32-bit: x86.zip http://www.mediafire.com/?7m7s13nt7j1yx7g
x64 / 64-bit: x64.zip http://www.mediafire.com/?ltunj607wk0pmoe
these driver from x86 drivers from, maybe an XP installation. just

extracted the x64 ones from a drivers.cab acquired from a 64-bit XP installation disc. Both x86 and x64 drivers are tested working in my system (Windows 7 x64 with the Acer 320U, at least.)