Okay, I don't own a copy of Biozone, but I'll do what I can (I assume we're talking about the inhibition of enzymes):
Competitive inhibition is when an inhibitor molecule directly blocks the active site of an enzyme, where the reaction with a substrate would normally occur. Because the active site is occupied by the inhibitor, the enzyme cannot perform its function, as shown below:
Non-competitive inhibition is when an inhibitor molecule attaches to the enzyme at a location
other than the active site. This distorts the shape of the enzyme, and ultimately the shape of the active site is changed so it can no longer accommodate its substrate. Ergo, the enzyme cannot perform its intended function, as shown below:
Another difference is that competitive inhibition is often permanent, while non-competitive inhibition can sometimes be reversed.