Power button does not work?

Hello everyone, I recently replaced my vibrator on my 3G and when I assembled everything back together, I find that the power button does not work. No matter how hard I pressed the power button it doesn't turn on. Then I thought to myself, "Did I miss something when I was putting it back together?" I plugged it in the charger and then it turned on. And another thing, that same day, the speaker above the screen (the one you hear out of when talking on the phone) it doesn't work anymore. I can't hear anyone when they call me, the only solution I have is to put it on speaker mode and then I talk to the person.

Any ideas or help please?

Thanks