Help Identifying Unique Values between Spreadsheets

I have a conference that provides me with an updated attendee list each week, and I need to compare this week's list to last week's to find new registrants. I thought this would be pretty straightforward but have been struggling quite a bit with it. Both lists are on separate spreadsheets in the same workbook. I need to compare both Column A and Column B (first name + last name) from spreadsheet 1 and highlight the unique values in spreadsheet 2.

Any help or guidance would be greatly appreciated.....