No, you cannot install iOS5 on your iPad 2
Yes, you can install iOS7 on your iPad 2.
Go to Settings > General > Software Update and you should find the update there waiting for you.
Connect to a WiFi network before you start the download.
Is it possible to install IOS 5 or 7 on my ipad 2. I have not been able to figure any way to do it, but I am just an novice.