WiFi event viewer has no connection with the fact the you have been hacked because the purpose of the software is to record and display events related to switching Wireless on or off, diagnostics status and error messages. If you say that someone has access to download software on your computer then this person could install another tool to compromise your system and get your email passwords and so on.
I would recommend changing the password to all the accounts you stored on your computer because the hacker may compromise other personal stuff you may have. Also, securing your computer with an anti-virus solution is the best thing to do at the moment. One free and good solution is to use avast! Free Antivirus which provides protection against all threats although it's free and has decent updates with the latest threats online. Install the software by downloading the setup package. During the install you will be prompted to first scan your computer which is highly recommended being in your shoes. By default, the anti-virus has a sandbox way of launching application in order to keep your computer protected and safe from malware or any other hacking tools.
