Are you running the latest OS, Lion?

The scroll bars disappear when you aren't using them. Just scroll, you don't need them to scroll. You'll get used to the natural scrolling or you can change that too. Just google it. Also you might like the trackpad better than the mouse.

http://heresthethingblog.com/2011/07...issing-scroll/

Anyway, the thing is whatever problem you are having getting used to Lion or the mac, somebody else has also had or somebody has written about it and how to change it.

-David