Not sure if this applies to 32 bit versions of windows or not, as I only use 64-bit. I have tons of ram and 32-bit doesn't handle it (max of 4 gig and you will only be able to use 3 gig due to memory addressing issues).

Anyways. I was running into an issue where I needed to scan some documents with an older scanner that didn't have drivers for Windows 8. So, I tried the Windows 7 64-bit drivers, after all you can get most Win7 drivers to work under Win 8 without any issues. Just an FYI, this scanner is a CanoScan LiDE 600F Model: K10291. The latest Win7 drivers on canon's site for this scanner work with Windows 8.

The issue was that Acrobat was not allowing the scanner saying it was missing scanintf.dll. Custom scan would work if you used the WIA version of the scanner. But I wanted the presets, which WIA (Windows Image Acquisition) version does not support in Acrobat.

The fix, add all the folders under c:\windows\twain_32 into your path. Easy to do. Open up a windows explorer window and go to the c:\windows\twain_32 folder. There you should see at least one folder. For the LiDE 600F there was a CNQ4802 folder. Now you just need to add that folder into your path. Open up your advanced system properties. Control Panel->System and Security->System->Advanced system settings. Click the environment variables button. In the system variables, scroll down to path, click edit. At the end, make sure you don't remove it, this variable is very important, add the full path to the folders in c:\windows\system32\twain_32\ preceded by a semicolon (;). Do not simply copy my path variable below and use it, as it is usually going to be different on every pc based on what software is installed. I did not need to reboot or re-install anything after making this change, but some people report that you have to, all I had to do was close and re-open Acrobat.

This is my path before:

%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;C:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\;C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\;C:\Program Files (x86)\Microsoft SQL Server\100\DTS\Binn\;%SystemRoot%\System32\Windows System Resource Manager\bin;C:\Program Files\Microsoft\Web Platform Installer\;C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\;C:\Program Files (x86)\Windows Kits\8.0\Windows Performance Toolkit\;C:\Program Files\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\;C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\PrivateAssemblies\;C:\Program Files (x86)\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files\Microsoft Data Protection Manager\DPM2012\bin\;C:\Program Files (x86)\Windows Live\Shared

This is my path after (I bolded what was added at the end):

%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;C:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\;C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\;C:\Program Files (x86)\Microsoft SQL Server\100\DTS\Binn\;%SystemRoot%\System32\Windows System Resource Manager\bin;C:\Program Files\Microsoft\Web Platform Installer\;C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\;C:\Program Files (x86)\Windows Kits\8.0\Windows Performance Toolkit\;C:\Program Files\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\;C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\PrivateAssemblies\;C:\Program Files (x86)\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files\Microsoft Data Protection Manager\DPM2012\bin\;C:\Program Files (x86)\Windows Live\Shared;C:\Windows\twain_32\CNQ4802

Well, I hope this helps people in getting their older scanners to work. Just a helpful tip, if you can't get your driver to install because it throws some kind of invalid OS error something, try running the installer in compatability mode. Note, XP drivers will probably not work for Windows 8, Look for Windows 7 first, then Vista, then as a last resort XP drivers. As always, I hold no responsibility for you damaging your system. All of this is at your own risk.