=IF(ISERROR(LOOKUP(A5,week1.xls!$A$1:$A$10,0)),IF(VLOOKUP(A5,week1.xls!$A$1:$D$10,3,0)>VLOOKUP(A5,week1.xls!$A$1:$D$10,4,0),3,0),IF(ISNA(LOOKUP(A5,week1.xls!$A$1:$D$10,4)>VLOOKUP(A5,week1.xls!$A$1:$D$10,3,0)),3,0))
Thats the formula using 3 IF statements.
Confusing?