What should I do? Any suggestions?

I got a iPhone 3Gs from a third party about a week or so ago. I charge it all night so it has a full battery for my day at college. But for some reason when I want to send a text at say 8:30 am it decides to turn off and then I can't turn it back on for the rest of the day as it just comes up with the logo and then turns off. Any suggestions would be lovely.

Mac and iPhone Wi-Fi connection problem?

I use N600 netgear router at home and sometimes Wi-Fi fails to log on. I do not get any message from the system. It just logs off. Not just my Macbook air, it happens to my iphone as well. But when I restart my modem and router, I'm able to connect to internet again. Does anyone have solution for this? Or should I use certain setting when I set up the router?

How To UnJailbreak An IPhone 4s?

I bought my iPhone 4s from a guy who used it for a while and had it jailbroken. I'm not all that comfortable w it being jailbroken bc I don't want it to lock up on me one day so my question is, is it possible to unjailbreak it and if so, how do I do that?

What Do you call this type of cable?

What is the name of the wire/lead/cable that fits from a headphone jack to an amp.

So I can play music from an mp3 player/ipod/iphone/blackberry headphone jack through my amp.