I would run Malwarebytes and SUPERAntispyware to see if there is an infection (trojan) on your system. Then I would change my email password to something complicated like: (example) *uSP<4nine@pVT after the issue is cleared. Contact your email provider and let them know.
Weak passwords can be broken easily.
Here, and free! http://www.malwarebytes.org/ Update the definitions before you scan and fix all malware found.
and here: http://www.superantispyware.com/ Free as well, same as above.
Any problems installing, come back here for additional help.
I've developed an issue with sending any emails. I can recieve just not send. It's complicated, but when I get the popup "windows security" to logon to imap.gmail.com and type in my username and password hit enter, the same blank request comes up again and again.
Thanks for any help.