I have a macbook that vibrates, so I decided to try to see if I could "fix" it on my own. All I did was loosten and then tighten the four screws (two on left, and two on right) on the macbook. One of my friends just told me that voided my warranty. Is this true. I mean, i didn't even take anything apart. And for anyone that is wondering, that didn't solve the problem.