I use Windows 7 x64 and ran into the problem of non-existent drivers for the Canon 20D. My solution was to install the Microsoft Windows 7 "XP Mode" software, whose installation process is explained at
http
/windows.microsoft.com/en-us/windows7/install-and-use-windows-xp-mode-in-windows-7
Once you've set up Windows 7 XP Mode and used windows Update to install all Windows XP system updates (a long drawn out process, since you need to reboot the virtual PC 3 or 4 times to pick up all the updates), you then need to go to the Canon support download page for the Canon 20D using the IE browser in the virtual PC
http
/www.usa.canon.com/cusa/support/consumer/eos_slr_camera_systems/eos_digital_slr_cameras/eos_20d#DriversAndSoftware and choose "Windows XP" as your operating system, and click on "Show All", and then download and install the following utilities:
Canon EOS 20D WIA Driver 5.4.1
EOS Utility 2.7.3
If you no longer have original CDs of the canon Utilities, you need to fool the above updaters in installation. This can be done by copying the all following lines into a file named CanonUtilities.reg on the virtual PC and double-clicking it to add the registration info:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Canon\EOS Utility]
[HKEY_LOCAL_MACHINE\SOFTWARE\Canon\DPP]
[HKEY_LOCAL_MACHINE\SOFTWARE\Canon\ZoomBrowser EX]
[HKEY_LOCAL_MACHINE\SOFTWARE\Canon\PhotoStitch]
[HKEY_LOCAL_MACHINE\SOFTWARE\Canon\EOS Capture]
[HKEY_LOCAL_MACHINE\SOFTWARE\Canon\EOSViewerUtility]
[HKEY_LOCAL_MACHINE\SOFTWARE\Canon\ODSK]
Once this is done, installation of the two utility packages (and any other of the Canon utilities you want on the virtual PC) can proceed.
Once installed, reboot the virtual PC, then put your 20D in regular communications mode and connect it to your host PC via the USB cable.
On the virtual PC's main window "USB" menu a "Canon Camera Attach" " entry should appear. Choose that (it has to be chosen each time the virtual PC is started and the USB cable is attached to the host PC), and the device driver installation process should start on the virtual PC. Once the installation is complete (I can't remember if I had to reboot the virtual PC yet another time), starting the EOS Utility should give you complete control of your camera through the utility program, i.e. choosing and downloading images, control via USB of shooting, camera settings, setting owner information, etc.
The only major restriction is that the EOS Utility on the virtual PC won't let you choose one of the host's PC folders as a target for automatically downloading pictures. But you use the camera in PTP mode on the host PC anyway.