well, to put it simply, windows 10 is basically microsoft's version of the current version of league where everything is out of control...mine crashes just by leaving it alone at times
not to dismiss things though, if your computer is 6 years old, I would recommend that if you know how, you begin replacing parts, but there are a lot of variables
interestingly, when I first installed league, windows 10 did have problems with it but I forget what fixed it...
if you are not on a subscription antivirus(paid for), then I suggest changing it to one of the free ones available. Microsoft basically dropped a disaster bomb with windows 10 but it won't be long until it is the only supported OS from microsoft as eagerly as they are trying to push it
other than that, as computers can begin to fail as early as one month (though not a total failure), 6 years might be a good time to use some extra cash to get your computer diagnosed at a repair shop so as to avoid a total failure if that is nearing