To reset your BlackBerry, three simple keys are all you need to know.
Left alt, Right shift and Right del.  Pressing those three keys, at the same time, will cause your BlackBerry to reset.
(the BlackBerry 9700 pictured has the three keys circled).

Resetting your BlackBerry weekly is a good practice to get into.

“Why?”, you ask?

A reset causes the BlackBerry to restart the operating system, and it frees up memory up as well.

It’s the very first thing I get my customers to do when they tell me their BlackBerry is behaving strangely.