Have you tried:
=Iif(DateDiff("d",Now(),[Warranty]) <= 0, 0, DateDiff("d",Now(),[Warranty]))
and (I'm assuming RW2 is set to above),
=IIf([RW2]<=0, "This Equipment is Probably Broken", IIf([RW2] < 14, "This Equipment is About to Break", "This Equipment Isn't Expected to Break For at Least 14...