Emails disappear from my Android phone every time I open Outlook 2007 on my Desktop. How can I fix? I attempted changing incoming server from POP to IMAP but the Outlook would not let me change it. POP server was the default.

You can't switch between IMAP & POP3, you must create a new account, using the same email address, then delete the old. If you have emails in the old account you want to keep, be sure you have a copy before deleting the old account. If Outlook is defaulting to POP3, use manual configuration to setup the IMAP account. Cox email servers & ports can be found here.