Excel: need to identify unique values across two sheets with multiple columns, need help ASAP please

[affyfiler]

Hi, I was hoping to find a way to identify unique values across two sheets in excel. However I want to do this with four columns grouped together, so it would compare four columns in sheet 1 against four columns in sheet 2 to discover if it is a unique value within the entirety of the list. This is because one of the lists in sheet 2 had rows removed from it, and some of the names in one of the columns have been changed based on new information, therefore I need to identify which ones these are in the original list (sheet 1). Hope that makes sense!

 

[oldbrewer]

loop through each set of data and if a match is found move on if no match label row in first group unique