Iphone 4s won't recognize on my PC (windows 7)

Hi, I've been trying to solve this for over 2 hours and still haven't found a solution to my problem.

Recently I had upgraded my motherboard and CPU, and had to reformat my computer to windows 7.
I downloaded itunes and plugged my phone in and it contiuned to disconnect and reconnect when plugged in. If lucky it would stay connected for awhile.
So i tried to find a solution for this through Apple help and it had told me to uninstall the my driver through Device Manager. So I did that and I restart my computer and plugged my phone back in. Now my Iphone 4s isn't recognized on my computer AT all. When i plug it in it says Unknown Device, I then contiuned searching for a solution and I tried everything. From reinstalling Itunes 3-4 times ( I followed Apple's How to reinstall Itunes properly ) and still doesn't work. I even tried to install the driver to my phone manually and still no success.
However when my phone is plugged in it charges... Also if i plug my phone in to a wall charger it also charges. And anthor thing is that I plugged my phone into my brothers computer and it recognizes my phone and i could access all my stuff (music,photos,etc)

I really need help and Im getting really frustrated with this problem if someone can help me it would be great. I think i've literally tried everything and I still can't fix this problem.

Please help me!