Showing task bar

I'm embarasssed to have to ask this question, but I can't figure it out.

I bought a 24" monitor and was trying to figure a way to increase the size

of all pages to automatically take advantage of the larger screen. Following

directions in Help and Support, I right clicked the task bar in the Command

Prompt and directed it to enlarge the page. Unfortunately, it did this only

for the Command Prompt page.

I've been trying to reverse the enlargement, but the task bar is no longer

visible. How do I do this?