Hello,
That's a workaround, not a solution, but haven't you tried a "Sticky Keys" option?
Just enable it and you will have what you like:
Holding the Shift key down while pointing to select in Explorer results in selecting multiple contiguous files. Holding the Ctrl key down while pointing to select in Explorer results in selecting multiple, non-contiguous files.
To switch it on go to Start -> Control Panel -> Accessibility options -> Keyboard or just quickly hit "Shift" 5 times 
Several settings could be adjusted as well.
Apply changes and try to highlight as you got used to: highlight an item -> hit Shift -> highlight others.
To switch sticky-key off double-click it with keyboard.
The same could be done with Control, Alt and Command buttons.
It is very convenient to monitor which keys are on/off from an icon in tray
Last edited: Nov 25, 2008