reprogram page up key on powerbook 12"

[madelson@pol.ne]

How can I reprogram the up arrow (page up) key on the powerbook 12"?

When I type rapidly, I sometimes miss the shift key (in the right lower corner of the keyboard) and accidentally press the page up arrow key (which borders the lower edge of the shift key). The result is that as I continue to type, this up arrow action overwrites some or all of the previously typed text.

During the day I type on several size keyboards, so I cannot maintain precise-enough aim as I am continually having to readjust to key spacing.

I need to reprogram at least this one key. Ideally, I could reprogram the function to disable the four arrow keys unless I also press another key. This would maintain function (at the expense of a little less efficiency in that I must also press an additional key) without the continual risk of deleting text as I type (when accidentally pressing the up arrow key; or being forced to type more slowly and/or look at the key board and my fingers as I type).