I just bought a pc fan without any connectors, didn't read the fine print. So now I'm stuck with this fan with the positive(red) and negative(black) wire. Now I need help as to how I go about connecting this to a 4-pin male molex connector?

If you have a Radio Shack in your area, they should have a female molex plug and the connectors that go in it. They should be able to help you. The black (ground) wire can go on either one of the center pins. The red wire should connect to the 12 volt connector, which would be the yellow power supply wire.