this issue has been raised before: Click Wheel works for restart, but not single button. there are other threads aswell but i cannot find them at present. There doesnt seem to be a clear solution, although some people have had success taping the connector down or cleaning it with IPA solvent
I've seen this issue to, a lot. but have yet to find a solution. It's something to do with the logicboard rather than the clickwheel or either of the ribbons that much i do know. Are people experiencing this problem mainly on water damaged units or is there just a problem in the design/manufacturing of some of these nano's that leads to this?
Hi Paul, opened it up and cleaned/dried it? or just the outside. if so was there any evidence of oily liquid. this needs to be completely cleaned off as detailed by mayer. if you do that and it is still dead it could be an issue with the oily make up in the keyboard/power button? What colour does the magsafe connector show, if any?
Probably just needs a replacement home button flex, these can be found on ebay. Although if your unlucky the contact on the logic board may have come off, these are replaceable too but the soldering can be a tad fiddly.
If the touch screen is completely unresponsive then check that the phone is still functioning properly by verifying it syncs with itunes and the the sleep/wake button works. If it seems to be working fine then you are likely to require a new touch screen/digitialiser iPhone 3G Front Panel Assembly
Firstly try restoring in itunes, then see if you are still having the same issues. If it's still behaving strangely after that i'd crack it open and inspect for liquid damage as the faint screen is often a sign of this.