Good old wikipedia always has the answer :) Corn Syrup (which is made from the starch of maize) is actually good according to here
http://en.wikipedia.org/wiki/Corn_syrup as Corn Syrup is made up of glucose. However High Fructose Corn Syrup has gone through a different (enzymatic processing, which means they are changing the molecules) process to convert some of the Glucose to Fructose
http://en.wikipedia.org/wiki/High_fructose_corn_syrup. High Fructose Corn Syrup is only produced because it's sweeter then plain old Corn Syrup. Corn Syrup is used in foods to soften texture, add volume, prevent crystallization of sugar, and enhance flavor. So basically they are two completely different things.