Same problem with my updated iTune and a first gen iPad.
Other forums suggested:
Leave your iPhone or iPad connected to your PC then:
- Quit iTunes
- In task manager click "show processes from all users", sort by description and stop any "Apple" processes and the image name AppleMobileDeviceHelper.exe
- Click Start > Run > in the Open text box copy & paste the following - with the quotes - "%ProgramFiles(x86)%\Common Files\Apple\Mobile Device Support\AppleMobileDeviceHelper.exe" and press OK. (or go to that directory and run that file)
- On some Windows maachines, the file may be in \ProgramFiles\ without the x86
- Open iTunes
This seems to have worked for some. Not for me. Still searching.
If your iTunes on your computer is version 10.7 or higher I'd suggest rebooting your computer and resetting your iPad.
First thing to try is to reset your device. Press and hold the Home and Sleep buttons simultaneously ignoring the red slider should one appear until the Apple logo appears. Let go of the buttons and let the device restart. See if that fixes your problem.
Then start iTunes on the computer and connect your iPad. If you are familiar with the old look of iTunes you can use the view menu to display the left column. Your iPad should be listed there.