I know this may sound like the dumb answer, but if you have a question like this one, I woul GREATLY suggest investing time in online tutorials or books. Since HTML is (obviously) widely used, tutorials are aplenty. Typing "HTML Tutorials" in Google gives more than enough results, typing "HTML changing link colors" or combinations of it, brought enough as well.
It is not that I do not want to answer, but rather, that you'll have plenty of other questions
