WiFi not able to turn on
I have problem with my phone this morning. First it didn't not connect to wifi so when i check in the setting, i found there is no wifi available shown in box so i did reset but still same couldn't find any wifi. then my email start crash. i can't open email app so i go setting again and delete the email account and add again so i can see my email again. then i start try to turn the wifi, it is become gray and not able to turn wifi on. i did reset and clsoe but still same. anyone have idea how to fix. Thank
iPhone 4S, iOS 5.0.1