Hi Guys

got an iPhone 4 with O/S 4.1

Yesterday I discovered that my YouTube app hangs when I try to run it, it stays open with the iphone status bar up and the window is black. I want to try a few things first so can I do any of the following :-

Can I rejailbreak my iphone if I do a full restore on iTunes

Can i download the YouTube (standard app in new iphone) app and overwrite the existing folder to try and fix it, if so which folder is the app in on the iPhone

is there any other option I could try before i restore the iphone, given that i can rejailbreak it

thanks for any help or advice