Safari not working on iphone 4?

I used cydia to jailbreak my iphone 4 and after that safari would just open for a second and then go back to the home screen. I used ifunbox to delete cydia from my iphone and it's not there anymore, but safari is still not working on my phone. Is there anything i can do? I have already rebooted my phone numerous times and this hasn't done anything.

You may need restore the phone.