ExcelBanter - Comparing ranges?

Guys, i'm completely stuck on this and hoping you can help. i have 2
columns with names. i need to compare column B to Column A. if a name
that is in column B is also in column A, then i don't need it. but if
it's unique to column B (it's not in column A as well) then i need
that name. i can't for the life of me figure out how to do this. i
was doing an IF function, but it's not working. i was doing this
=IF(B2=A1:A443, 'NO', B2). so basically, if the name in B2 is found
in the range A1 to A443, then type NO, if the name in B2 is NOT found,
then give me the name that is in B2. this function is not working
though. can you help me out?

Thank you

Carla