Hi Mad_Sunday.
Right click on a desktop and choose Desktop Settings. Now that the Desktop Settings window pops up go to the Mouse Actions tab in the left pane of the window. Now click on the red - next to the Vertical Scroll setting to remove it or just change the option for Vertical Scroll from the Switch Desktop to something else.
Regards.
Andy
Yahoooooooooooooo, give that man a beer. I, and my sanity thank you!

Pete
Hehe glad I could help Dude.
Now go to Your first post in this thread, click on modify button and add [SOLVED] to the beginning of a subject line so it looks like this:
[SOLVED] Desktop change by mouse wheel, how to turn it off?
and re-submit the post

.
Regards.
Andy