Last week Mcafee firewall went of all the time. Although the message appeared firewall works fine, you are safe, the firewall was off. I could not start it again. I tried to uninstall and reinstall it several times. Did not work. Some viruses and Trojan horses detected. Could not remove them. Yesterday same problem with other computer.
What is that thing that turns off the firewall of mcafee?? My computer man is reparing the thing now.
If your computer man is repairing them he's the best one to tell you what was going on, but some infections can indeed turn off security software so always keep your system totally up to date, be careful what you click on or download too. Whilst security software does it's best to protect you nothing is 100% guaranteed unfortunately because there are 100's of new infections out there daily plus variants of old ones so it's a constant game of 'catch-up'.
You might consider some extra 3rd party tools to keep as a precaution. There are some listed in the last link in my signature below.