Help With Restore!!

So my friend had an iphone 4 and at a party someone put a password on it or something but he was upgrading to the 4s in the next few days or what ever, so i asked him if i could have his old one, he said sure, and gave it to me. so now im trying to restore it now and when i try to it says preparing iphone for install. but it wont go further, its not jailbroken but idk what to do help!! and after a while i get error 1604

 

And its not stolen, cause im not that much of a jackass..

 

Mods, you can close this, problem solved.