IPhone4S is not allowing to text; use email nor certain apps

if you still have warranty on it :

I would suggest you restoring the iphone to factory settings and taking it to the nearest Apple store.

else :

I believe there is a hardware issue (loose connection). Since it is a 3G iPhone (warranty may have expired unless you got AppleCare), it is not difficult to open up and see whats going on inside.

Hope it helps!

p.s : When you say 'stroke of luck', things get interesting. You may put your iPhone in Restore mode and then see if iTunes is recognizing it (if you at least have any charge, only then will it be possible to try this!).

Yes, you can. Just reset and restore. The backup is from yesterday, so only that information will be lost which you added today. Everything will come back. But it will take time if you have a large camera roll or lots of apps.