Why is my Samsung Eternity going so slow or not responding to my commands?

Ok so I got my Samsung Eternity about a year ago and it's model SGH-A867. It has run fine until these last two weeks. It started going very slow and sometimes it just doesn't respond to my commands. Is there anyway I can fix this by myself because I live far away from my nearest AT%26amp;T store. Please it you know anything tell me.|||Yourself could secure to be fixed for you