I can't find the fallout 2 insallation directory I'm running 32 bit vista, any help would be greatly appreciated.

If you used default instalation path it should be in C:\Program Files\GOG.com\Fallout 2\
If not, right click the game shortcut and choose properties. It should show where the game is.

The shortcut will only bring up the shortcut's directory, not the actual installation path.
Type in whatever you named the file (should be fallout 2) into the Start Search option in the start menu, right click on the file name and click properties.

I'm only using XP, but surely you can Right-Click on the shortcut, select "properties" and in the "shortcut" tab (which should open by default) there will be a box "Target" which should have the target of the shortcut...

oops maybe you're right. I was tired :)