Windows 10 update not working so well

I updated from 7 to 10 a while back and right from the start it just was not right. Programs open extremely slow and performance is lacking. I have an older PC with a slower intel processor and less ram that runs better. Last week I restarted my PC and it basically reverted back to what looks like the original 10 upgrade. Luckily I was able to use system restore to get all my stuff back but something is not right. At this point I just want to save some stuff and hopefully do a new clean install of Windows 10. What exactly do I need to do? I have two other PC's and a laptop that are running 10 just fine.

http://lifehacker.com/how-to-do-a-cl...-10-1720775893

http://www.tomshardware.com/faq/id-2...l-windows.html

I haven't tried to upgrade yet from my windows 7 to windows 10 and my primary reason is because it might not go well with my laptop. I heard that it should also be compatible with my device before doing the upgrade. I'm also contemplating about the windows 10 upgrade even it comes for a free install.