Gidget, you wrote the equation as:
IF(UPPER(B41)="x" (Applies to all conditions below)
And
IF(S8:S13="x",0,"")
Or
IF(C1<=3,C1*C41,"")
Or
IF(C1>=4,45,"")
However, the inherent problem with that is that you have " " at the end of each of the OR items. For example, you evaluate S8:S13 for "x". IF it is true, then you return a 0. If not, then you return " ".
What do you want it to do if it finds an X in S8:S13, and it also fins that C1 <=3? If this is not possible, and you are actually intending to just chain all of these together, then you should have something like this:
IF(UPPER(B41)="x", IF(S8:S13="x",0,IF(C1<=3,C1*C41,IF(C1>=4,45,""))),"")
However, doing this results in an error in the returned value because the formula is unhappy with the evaluation of S8:S13="x". What are you trying to evaluate with this?