1-phone 3GS Home Button Ways Solutions
2- solution
It's very simple.
The same thing happened to me, the start button stopped working, I did and it worked. So I hope I'm not only a false rumor, which is convenient and directly worked for me.
Hold the home button and power button for 10-20 seconds until it resets.
When it comes back later, the Start button works again.
Remember that the iPhone is a small computer, and must be restarted every so often. Just like most of Apple Computer and Microsoft, is not only a mobile phone, and this may have something to do every few months, quickly rebuilt.
If this does not work, then you have a real problem, bring it back to your store and get a replacement. I hope you were smart and took out insurance and the whole process should be very easy.