This post from Chazm solved it: simple really!! Thanks for your help...
Didn't read the whole post but I am assuming you can't scroll either up or down.
Easy fix:
1. Turn phone off (or you might access something unwanted)
2. Push real hard on the track ball
3. While pushing in, scroll up and down.
4. Do it a couple of times and it should be fixed.
Again, I read this post real quick so you might have another prob.