Home button is not working

I dropped my iPhone 3G after 3 years of (hard) use, this cracked the glass. I then got a new 3GS, and used the old 3G as an alarm clock. One night I reached out for a glass of water and knocked it over. The next morning the 3G was making crackling noises, so I dried it out but she was dead, Jim.

So it lay on my desk for some months. Then I decided I would fix it. I got the new front cover and glass, (no home button) and also new docking electronics. Replacing these went smooth as advertised.

So when I charged it and switched it on, I was happy to see that everything seemed ot be working....except the home button. Nothing. Press hard, sideways, up down, nothing nothing nothing.

So I said some words, ordered ANOTHER front screen assembly this time with the new home button and plastic and stuff. Installed it no problem, but....exactly the same problem. Home button she dead, dead, dead.

Any help, much appreciated.