When I try to sync my iPad with my pc through iTunes, I get a message that my iPad is not connected. But it is connected. I don't understand the problem. It's really boring. Most funny is that in iTunes , under devices, I can see my iPad.
Have you updated your ITunes to the latest version? It could be that you are running an old version of iTunes and that it cannot read the new IOS 5.1.
Yes, that happens with my iPhone 4 as well. But it's rarely, it could be worst though. You could do a factory reset and upgrade it with 5.1 or 5.01 if you're shsh with tiny umbrella for jail breaking purposes. Make sure you back up.
Usb 2 I was having the same issue. I was plugging my iPad 2 into a USB dock. When I plugged it directly into the computer's USB port, it synced! I hope that helps.