Hey all,
I am just here to report that there is an issue with this pack of items being used on windows xp...I have gone to my "Display" options and when I browse and select the Abe.Theme it comes up with an error stating that a file(s) is missing from the current location of that file when all I did was extract the "Deskop Theme" folder from the zip and that was it...
---Stixsmaster

From the Readme that's buried in the folder:
"If you have Microsoft Plus installed on your computer you
can most easily use the Abe's Oddysee desktop theme."
Now, Microsoft has discontinued Microsoft Plus!, so this isn't an option.
Basically what follows in the Readme is that you'll have to set up each piece of the theme manually. It's formatted terribly in the Readme so here it is in bullet points:
MOUSE CURSORS:
- Open the "Mouse" options from the Windows control panel.
- Select the "Pointers" tab.
- Select a cursor you wish to change, and hit the "Browse" button. Find the directory you extracted the theme to, and select the appropriate cursor.
- Repeat accordingly for all the other pointers.
SOUNDS:
- Open the "Sounds and Audio Devices" settings from the control panel.
- Select the "Sounds" tab.
- Under the "Program Events" window is a bunch of events upon which the sounds occur. Basically do what you did for the mouse cursors, but with the events in this list.
Hope that helps.
PS. Team GOG, it might help if you put the Readme txt file within the zip file OUTSIDE the "Desktop Theme" folder.