Excel "Clear Contents" is also deleting formulas

I've duplicated a worksheet and want to clear the contents but not the formulas. I know going to Edit > Clear > Contents is supposed to clear the data but leave the formulas intact; however, it's clearing my formulae as well. Any ideas what might be going wrong and how to fix it? :S

(Second question would be where best to post this question, as my community selections seemed somewhat limited!)