Why does Itunes not recognize my iphone 3GS on any windows computer?

I have had my Iphone for a little while now and itunes on my computer was working and the phone was doing fine except that the usb wall charger would not charge my phone in less i plugged the phone in first, turned it off, then turned it back on and then the wall charger would work correctly. This was more irritating then anything and I had read on the internet that updateing to 4.3.1 would fix the issue. So I was using iOS 4.2.1 on my iphone 3GS and decided to go ahead and update to 4.3.1, after doing so itunes (newest version) will not recognize my Iphone no matter which computer I plug it into (I have tried 3 other computers, 2 of which run Windows 7 64 bit and the other running Windows XP 32 bit). I have tried reinstalling the newest version of itunes on 2 different computers which included deleteing ALL folders and/or files related to apple, itunes, quicktime, or any other program that i may of had on that computer. I also uinstalled the apple mobile device driver in Device Manager to try to see if that would fix the issue at the same time. None of that worked on either PC. I then tried connecting my Iphone to a computer I had never had it on period. This computer also never had itunes or quicktime on it so i figured this would be a fresh start. I again installed the newest version of itunes and then connected my Iphone to that computer for the first time, which again resulted in not working. My last try was connecting my Iphone into my brothers computer that already had itunes on it, and he has a ipod in which he has used on that computer many times, his ipod still connects and itunes recognize's it just fine, however again itunes would not recognize my iphone. Next I thought maybe if I put my iphone into recovery mode and then connect it to my computer itunes would find it, which would correct the problem after I exited recovery mode. Yet again to no avail, and i tried this on all 4 computers as well... Lastly I tried to just reset my iphone and let it come up while connected to the computer, but sadly, to no avail.

So obviously my conclusion is what ever is causing this problem is most likely located directly on the iphone itself, seeing as I have tried it on multiple computers one of which itunes and the phone had never been on, 2 of which I have previously used for my iphone on iOS 4.2.1 and another of which was my brothers which he had used for his ipod. However I do not know how to fix (if I even can) this issue so that I can once again use itunes with my iphone.

Oh, and lastly... updateing from 4.2.1 to 4.3.1 did not fix the usb wall charger issue... After all of the above all I achieved was to add another problem to the table of which previously consisted of a problem that was simply irritating and annoying.

Thanks in advance for any advice and/or solutions that may lead me to resolving this issue.