Malware Bytes (as stated above), along with CCleaner, Advanced System Care.
That's the recommendations for software, but the real recommendation is to do a clean install of windows. You won't believe the difference a clean install will make to your machine. It's the age old issue of not wanting to spend a day or so reinstalling everything, but it will save you a ton of time in the long run. It will be like having a brand new computer again.
Ok, bring on the "that's overkill" responses. This option can be refuted, but the reality is that there isn't a piece of software on the planet that will give you what you're looking for. A clean install will.