Iphone 4 black screen, unresponsive?

Me iphone 4 is completely unresponsive and has a black screen, but when i plug it into the computer it gets into an endless loop. The apple logo will show up then the screen goes black and do it again and again and again and again.itunes doesn't recognize that its plugged in so i can't restore it.

What does a iTunes backup actually back up?

When iTunes recognizes your iPhone and you right click on it and click 'backup' what things actually get backed up? Do photos, videos, notes, text messages, apps, stuff like that get backed up? Or only the settings. I've looked for this answer for forever but i have had no luck.

When I call someone they can barely hear me?

I have an iPhone 3S and when I call someone or they call me, it sounds like I'm whispering to them and they can BARELY hear i have to yell into my phone so they can tell what I'm saying. I didn't drop my phone or anything it just happened, can anyone help?