The problem is once you help them, they expect it again and again. And it will happen again, because they're often the ones responsible for the problems. And really, this stuff can take many hours to troubleshoot, or even days. So, I generally don't do it anymore. I have enough of this crap in my own household - 3 Windows PCs and 3 Macs. In fact, I'm backing up my OS X 10.11 iMac right now, in preparation for the update to macOS Sierra.
Furthermore, I don't want to be blamed for important files they may lose or may have already lost because of their own mistakes.
I even turned down my father-in-law's request recently. It didn't go over so well, but I had some pseudo-legit excuses. I'm 90% sure his setup is full of malware, so I probably saved myself half a day's work.
This problem is mostly resolving itself, thanks to smartphones, tablets, chromebooks, and ultrabooks. Hardware with few (easily) user serviceable parts, and operating systems that have an easy recovery and restore option. Cheaper laptops are practically throwaway commodity appliances now, too.
I can open up a smartphone and replace the display, or take apart an ultrabook or macbook with the help of ifixit or a youtube video, but it's not worth the trouble 99% of the time. Even the phone repair people who have kiosks in the mall won't be there forever the next time display tech advances. Companies like Apple already make it hard because of security measures, and non-removeable batteries are now the standard. But mostly people are just replacing their devices when they break, anyway, rather than having them repaired.
People do still have desktops and larger laptops, but the number of people who use them as their primary computers is dwindling. Of course, this isn't really good news for old school mom and pop repair shops. Eventually they'll go the way of television repair shops. Not much you can do to fix cloud software, either.
Those of who use powerful desktops are our own IT, so we'll at least be doing our own repairs. But it's really not long before casual desktop users asking for help fixing their computers is an uncommon occurence. Kids are being raised on touchscreen devices with soldered on/enbedded hardware that would take a team of engineers to repair. The mainstream desktop is going to all-in-ones, thin clients, NUC/mac mini-type PCs, and "sticks". Computer broke? No problem! Go to your local CVS, pay $30 for a new stick, done. All your stuff is in the cloud (or wirelessly networked external drive, if you are fancy), anyway. And when VR/AR hits peak use, it will be primarily powered by consoles, smartphones, and embedded computers.
10 years from now we'll be looking back with some nostalgia (but mostly we'll appreciate not being IT for friends and family) on the days when it was possible to fix computers yourself without expensive equipment and several degrees or certs. Similar thing is happening with cars.