I had a similar problem too after I upgraded from Android 3.2 to 4.0.4. One difference though is that I did find that some computers would connect, but any computer I had previously connected it to would not work. The only fix that ever worked for me was a factory reset; it's fine now.
It might be worth a try to do a factory reset. You can back-up your files using a cloud service such as Google Drive without the need to plug it into a computer.