Replacing ceiling light with fan/light combination
If you don't know how to use a test device of some sort -- at least a voltage probe light -- you really should not be taking apart and reassembling your house wiring. The chance of hurting yourself or someone else is too high. Get a more knowledgeable friend to do the project with you, teaching you as they go.

Having said that...

The house-wiring color code is fairly well standardized, at least if whoever installed the circuit was vaguely competent. A table giving the conventions for multiple countries can be found at http://www.allaboutcircuits.com/vol_5/chpt_2/2.html

In the US, the black wire would normally be the "hot", or powered, connection and the white wire would be the "neutral", or return, connection. The switch should be on the hot side. So a lamp is normally connected to the black and white wires, with the safety ground (green or bare) wire running to the body of the fixture to ensure that a short circuit, if one ever arises, causes the breaker to blow rather than zapping a human.

A red wire, in the US, is the "second hot". This is used when two circuits are run through a single cable. It's sometimes used for the connection between two-way switches (the first switch selects which of the two will be powered, the second switch selects which of the two will be connected to the controlled circuit, so the two switches have to agree before electricity flows). It's also sometimes used in exactly the situation you're describing, when there are two wall switches independently controlling two parts of a single fixture (the fan and the light, for example). 

The fact that the red wire is present at all in a US installation would tell me that the box the fixture was mounted to had probably been wired in some specialized way, or at least that whoever installed that wire expected to need that wire later. (In the latter case, it may not be connected to anything at all right now.) If you can't figure out what controls that red wire, capping it with a wire nut and tape was almost certainly EXACTLY the right thing to do.

So... If that's what you've done, and you aren't getting power, either your connections are wrong or they're bad electrically. Cut the power, dismount the fixture, review the instructions that came with it, review how you actually had things connected (no assumptions!), make sure that you have connected the wires to each other properly, make sure no bare wire was exposed that could have caused a short and blown the breaker... did you check that the breaker hadn't popped? ... and fix whatever you've done wrong. If you can't figure out what you did wrong, go get that more experienced friend and have them look at it. First thing I'd do, since you didn't note how the old fixture was connected, would be to determine whether the circuit really is wired as the colors promise, and  whether the wall switch you're using controls the black wire or, possibly the red. (Or was installed in the neutral, which would be WRONG but is unfortunately possible in circuits installed by amateurs.)

WARNING: Ceiling fans are heavy and they vibrate. It is generally considered a Bad Idea to hang one from an electrical box that previously carried a lamp fixture unless you KNOW that it is unusually well secured and will not work its way loose and drop the fixture on someone's head. If the box isn't screwed directly to a joist -- and I suspect even if it is, by code -- you'd want to replace that box with one designed for the purpose, screwing the ends of the hanger bar into the joists on either side of the opening and bolting the box to that bar.