I have an older computer too, I got rid of MacCaffey and started using the Microsoft Security Essentials that came on my computer (which was also FREE). I cannot believe how much faster my computer is now!!!
I’ve had no security problems yet - but boy, I sure did with MacCaffey - got a bad thing on there that kept popping up porn sites on my desktop - all the while my MacCaffey scans were showing no problems!
My computer runs like it did when it was new now.
Yep, I have cleaned up a lot of computers (old & new), and most of the time the problem is not a virus, trojan or root kit, but an adware infection.
One of the most common parasites is the “weatherbug”. Talk about a scam.
Of course there are all the games that have adware as part of the install too.