Iphone won't let me view contacts?

I just got my grandpas old iphone and it worked fine until i downloaded new software and some apps. Now when i click on contacts and click on a name it won't open it up, it just goes straight to the home screen.also, the + button is gone and instead there's an arrow like a refresh button on the other side, and i don't know what that does because it doesn't work when i click it. And more, i can't go into the mail, contact setting,
because it does the same thing that it does when i click on a contact. Is there anyway to fix this without having to restore it? If not, how do i restore it?

You can see if you need to update it by plugging your phone into a computer, clicking on the phone under devices and click check for updates under the summary screen. If that doesn't work, you can restore it by plugging it into a computer and click on it under devices and click restore. (It's on the summary page right under check for updates)
Hope this helps.