How do I use this cable to connect my PC to my TV?

I bought this cable off Amazon a coulpe days ago, in the hopes of watching movies from my computer on my TV with my family. One of the "questions" asked was "Will this cable let me watch movies from pc on my tv?" to which the answer was a simple "yes", so I bought it.

It arrived today, but when I plugged it in, nothing! I double-checked with my Gamecube to make sure the jacks worked on my TV, which they did. I have nothing to test the cables on, but since they literally just got here I'm assuming they work fine.

Does anybody know how to do this?