How to connect 14 monitors using one cpu

The cpu is not really an issue here, the Graphics card is what allows multi-monitor set ups,
several Asus cards allow six monitors on one card, my 6950DCII's for example, given the right monitors I could hook twelve screens up to them, with three of them you could power eighteen monitors but for such a build its designing it in from the very start, not usually an addon capability.
do you want all fourteen showing the same picture spread across them all or are some going to display something else?
and what is the rest of your set up there?
your motherboard may not even support sufficient Pcie cards to try this, let alone your Powersupply  
Post full specs and I'm sure we can get to grips with this one easier
Moto

Well if you don't need powerful 3D facilities there are companies like Matrox that have reasonable multi monitor support, they have cards that do 8 monitors a piece. Not cheap, but there again 14 monitors are quite pricey too. I'm sure there are a few others too, even AMD allow 6, I'm kind of assuming you are not after consumer grade.

It is a bit of a niche and professional area so I suggest you outline what sort of thing the box will be doing. You might get a few more suggestions and maybe some ideas thrown in that may give you different avenues to explore. Alas I'm no expert on these things.