If the plugins and widgets were not the culprits of the security weakness to your site have you looked at your computer?
Sometimes, things appear to be happening to your site but in reality it could be coming from your computer.
When did you last run a malware program or virus checker on your computer?
BROWSERS
Browsers and computers are very susceptible to hacking, and it is crucial that you do some housekeeping on your system, at least, on a weekly basis.
PROGRAMS THAT MAY HELP
At this point, I wish to state that, none of these programs are affiliate links or are of any financial interest to me. They are provided solely to help you solve your problem.
CCleaner
https://www.piriform.com/ccleaner
CCleaner is a free program that clears unwanted files, browser cache, registry errors and a host of other things from your computer. It can even help to speed up your system.
Virus Protection
http://home.mcafee.com/downloads/free-virus-scan
http://www.kaspersky.co.uk/free-trials
This list represents only a few of the many virus protection programs available to protect your computer.
Malware Protection
As it the names says, protects your computer from malware and it is Free to use.
http://www.refreshyourcache.com/en/