The next time you've got some money to spend, invest in Norton Internet Protection Suite for Windows - it costs about $60 USD or more, plus an annual subscription fee (in the $30-60 USD range) but it includes AntiVirus and Spam-Control and a decent software-level Firewall against intrusions, malware, etc., and can be downloaded online via
Endpoint, Cloud, Mobile & Virtual Security Solutions | Symantec - if that becomes an option for you. Good job on isolating the bogeyman this time, but, of course, in the best of all worlds, you'll have something solid that gets updated every couple of days, from a well-funded company, that can prevent as well as remedy. Just a thought.
I use to use Norton 360 and our computer got taken over and damaged. I scanned the computer for hours using Norton and Malwarebytes found the malware in minutes so I complained to Symantec and they offered me a more expensive version for free which they claimed was better so I told them I didn't want it because they didn't have their best interests for me from the start and I swore that I would try better software first before ever coming back to them.
I think that Norton was first built on an anti-virus perspective and you really need a company that is built on both anti-virus and an anti-malware perspective. You need to have anti-virus definitions automatically downloaded from the cloud because if you are waiting for the update from Norton, you are essentially unprotected from the newest threats.
No security software will detect all malware. If you're infected, I think the best thing to do is to scan your computer with several good programs. I've used malwarebytes, Bit Defender, AVG, and some of the Kaspersky tools.
I've found the best way to avoid getting infected is by not downloading the free stuff. It usually has a lot of stuff you don't want and some it is really harmful. Anytime I download any free software, I check to see what programs I have installed before downloading and after downloading. Then I delete the junk that comes with what I want. If my browser is acting differently, I check, my browser setting, extension, and plugins.
I think this is a pretty good laundry list of tools to disinfect a computer, although I have not used them all.
 SUPERAntiSpyware Portable Scanner
 Kaspersky Virus Removal Tool
 Dr.Web CureIt
 Microsoft Safety Scanner
 Trend Micro System Cleaner
 Trend Micro Fake Antivirus (FakeAV) Removal Tool
 Trend Micro SysClean Package
 Norman Malware Cleaner
 VIPRE Rescue Program
 AntiVir Removal Tool
 McAfee Avert Stinger Tool
 McAfee FakeAlert Stinger Tool
 Microsoft Malicious Software Removal Tool
 F-Secure Easy Clean
 MicroWorld eScan AntiVirus Toolkit (MWAV)
Other Free Virus/Trojan/Spyware Removal Tools by Anti-virus vendors:
 BitDefender Virus Removal Tools
 Kaspersky Virus Removal Tools
 Panda Virus Removal Tools
 SOPHOS Resolve Virus disinfection tools
 Symantec Virus/Trojan Removal Tools
 Symantec Security Risk/Spyware Removal Tools
 Norton Rescue Tools: Norton Power Eraser
 AVG Removal Tools