It is very unlikely that Windows 10, per se, is at the root of the problem. As I said earlier, but in more technical detail, building a house on quicksand, which is what upgrading to Windows 10 over an earlier installation of Windows that is in questionable condition, is quite likely to result in issues as time goes by.
At 7 years old even most low-end machines can outstrip what you have in terms of performance if you go with a newer CPU/APU.
I can't say for certain whether or not you're there yet, but a lot of people expend a great deal of effort, and money when they hire a pro, to extend the death of a machine rather than doing the smart thing and replacing it. I have told many a client that it is not cost effective for me to be repairing (or attempting to patch up) their old machines, but if they insist after I've given them my professional opinion then I'll do it. It still doesn't make any sense, but they're then going in with their eyes as wide open as I can make them.
I have yet to see a machine that ran OK with Windows 7 have any issue with Windows 10 as it currently stands if a clean install is done. I have, in fact, seen Windows 10 breathe some "new life" into old hardware, but even then that will not hold into the perpetual future. Hardware does have a service life, though most of the time it seems to me it's the demands of new software, really, that ends up being the death of older hardware. Nothing is so constant as change, and in the world of computing change is always "on steroids."
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
Memory is a crazy woman that hoards rags and throws away food.
~ Austin O'Malley