i tried to restore the backup onto my ipad and it asked for a password

I was trying to update my ipad using my computer and it wouldnt work so I went online and it said to update itunes so I did after that I went into my ipad and I started using facebook then my ipad turned off for no reason I looked at the computer and it said ipad in recovery detected to use ipad you must restore it or somthing like that so I cliked restore thinking I could just get all my stuff back because I had backed my ipad up this morning after it had finished I clicked restore to backup then it said enter the password to unlock your Ipad backup I didnt know what that meant so I tried my AppleID password my Ipad password and every other password I could think of I even tried my old Apple ID password and my computer password but nothing will work.

Please help I need the stuff for shool!