Home button unresponsive, no audio output, and unable to charge?

Hello,

I have suddenly found that the home button on my iPhone 3GS is completely unresponsive--I am using Assistive Touch as a replacement. Additionally, audio only plays through headphones (except for ringtones, text-tones, etc.; those do not play at all). Also, my phone has no reaction to being plugged into a charger that has worked for the past several months without fail. It also does not connect to my laptop on iTunes anymore.

I do not see any red indication of water damage, please help of you can. Thank you.