Computer recognizes husband's iPhone 4 but not mine. Why?

My husband and I both have the same iPhone 4's, 2 years old. I back mine up through iTunes regularly and was trying to do so a few days ago when iTunes kept freezing up during the steps and I had to get out twice. When I went to get back in, the computer wouldn't recognize that my phone was hooked up and popped up 'USB Device Not Recognized". I Googled, and troubleshooted, and did a million things. Updated iTunes, restored my computer, uninstalled USB drives and reinstalled, restarted my phone, tried to update the drivers but it said they already were. So then I plugged my phone in on my husband's computer… Still didn't work. I plugged HIS phone in on his computer and it worked perfectly.So, I knew the USB cord was working fine. I then plugged his phone in on MY computer. And it worked! So my computer is not the issue… It's my phone? But how, why? What could've caused it and more importantly, how do I fix it? I plan on selling the phone when my iPhone 5 comes in the mail, but I need to first transfer everything from it to my new phone. Anyone know a fix for this?

I didn't read any of this

The best anwsee is that his was recognized first. I had this same problem with my girlfriends computer, so we contacted costomerservice, and they sent us a free second account for me to use. Hope this helps!