comparing 2 columns

Suppose I have the following;


[A1] QWE RTYU [B1] QWE RT [C1] QWE RTYU
[A2] ASD FGH [B2] ASD F [C2] ASD FGH
[A3] QAZ WSX [B3] GHJ KL [C3] 'QAZ WSX' NOT FOUND

Column A will always be larger (greater # of rows) than column B.
Cells that do not match I would like to use shading to indicate. (I think I will use conditional formatting for this purpose).

I have being using the 'VLOOKUP' function, but this is not really suitable for my needs. Ultimately, I want the file to be user-friendly and automated.

I have also tried using 'IF(COUNTIF(RANGE,CELL)>0,"",CELL & "NOT FOUND")'.