I have an iPad2 model MC979PP/A with Ver 8.0.2 (12A405). In response to an upgrade notification, I downloaded Ver 9.3.5 on my iPad. I clicked the "Install" and it hangs. I can't figure out what is happening. The WiFi is good, the iPad is fully charged. I tried to "Ïnstall" another time several times, and it hangs everytime. Please advise what am I doing wrong? Why is the "Install" facility is not working. Thank you.