I know this thread fizzled out more than two years ago, but I want to thank thank thank the expert who posted the assistance. I have a 6-month-old daughter who loves to punch keys and she somehow disabled the touchpad. This post gave me the lead to solve the problem: hit Fn+F6. That toggles the "disable touchpad" function.
This has been driving me crazy for more than a week, and I haven't been able to find the solution anywhere, including the Gateway user's manuals, google searches, nothing.
So, thanks, friend.