Need help

I sent this message this am but it didn't show up--maybe I didn't put a subject, or maybe I am asking the wrong thing--but here goes again. I have a 3-month old computer, bought from a leading mfg but have had nothing but trouble, trouble, trouble and I want to see about returning it. I have a year's warranty. Have any of you done this--I don't know how to go about it, and if I have a snowball's chance of it happening,. Any thought would be appreciated. Thanks