If scanner compatable with vista will be compatable with windows

It "should" be, if W7 hasn't got native drivers, Vista's should work ok.

some of the low end canons don't support 64bit vista or win7, i've had to buy vuescan to get mine working

if Vista Drivers are posted you can try a 50::50 chance of installing the drivers in compatibility mode.

Try the Above only if Windows 7 Drivers do not work or the native drivers..