If you have a 64bit Windows OS you already have KPP enabled by default. 32bit doesn't get this benefit. KPP is always a benefit to prevent rootkits, but that's only if they actually get that far. Place up some perimeter hardware and local software protection and you'll have some nuisance intrusions but you'll do just fine keeping most bad stuff out. Keep a decent AV/AS/AM protector on. This thread is pretty old in advice on what to use, but lately the better ones have consistently been Malwarebytes, Superantispyware, Vipre, Bitdefender, Sophis, Windows Security (built in). You can also add some ransomware monitoring like OSarmor and Acronis Ransomware Protection. Can't hurt. Also get a VPN for your more "sensitive" sites.
Also PCs are so powerful today and with multicores the system isn't bogged down so much like they used to be, except only for active drive scanning and email monitoring.
And some guy before mentioned the best protection is education. There is no greater truth than that. You can load up with all the protections possible but if you visit random sites by link hopping, you're still in worse shape than someone who has no active protection and only reads news and sports sites.