Is value a2 in B:b?

Hi,

I am up against the clock, and I need to know how to display in a cell "Yes" or "No" based on a value being (or not) in a column.

I have column A with values, and I want column C to show Yes/No based on if value x from say A2 exists as a whole matched valued in B2:b3000 and set c2="Yes" if it is, and no if it isn't.

I have tried to work this out my self, but being under pressure it's not making much sense, and I could do with a hand.

Im sure the answer must have been presented here, so even if some one can direct me to a post that would be good.

Many thanks in advance