Currently Being ModeratedOct 17, 2013 6:29 AM (in response to Rhsb1221)
Thank you for the details of the issue you are experiencing with Wi-Fi on your iPhone. I recommend the following article and specifically steps 4 and 6 for the situation you described. Step 4 says to restart your phone, but if you click on the link in step 4, you will get the steps to reset your iPhone as well.
If the issue persists after following those steps, I recommend the steps in the section titled "Unable to connect to a Wi-Fi network."
Thank you for posting in the Apple Support Communities.
Currently Being ModeratedOct 17, 2013 6:35 AM (in response to Rhsb1221)
This issue is affecting several iPhone 4 users. See this discussion.
There are enough people reporting the problem that Apple does have a compatibility problem between iPhone 4 and IOS 7. Whether it is hardware that is not appearing because of IOS 7, or a problem in IOS 7 is up for debate. Regardless, Apple needs to take note and resolve this issue.