Hiding Fields

I can't seem to find anyway to implement this, but what I want to do, is for contacts hide certain fields from showing up unless another field deems it so.

In my case, I want a field to ask me how many computer's the client has. If I state with a pick list that the Contact has 3, then it will show 3 sets of fields on the Contacts account asking details about each computer.

The only thing I can see to do at the moment is to make as many fields as the highest I would think and have a lot of clutter for each Contact regardless of how many they acually have.

Let me know!