Hi guys, I've got a question for all of you. My Macbook Pro keyboard is acting up. I cannot get the "r", "4", or the volume down button to work. The only way that I am able to type this is by copying and pasting the letters in. Are there any troubleshooting tips that i can try, or do I just need to take it in to have it serviced? I bought it back in late July, and it is a 15" 2.2 Macbook Pro. Thanks.