Well, I'd at least start with the antivirus, depending on what if anything you use, I'd just use windows defender or another of the free ones like avira free antivirus which is very good too. Make the definition is up to date before you scan.
Then do the malware scan. I recommend Malwarebytes. If nothing comes up there, then do the rootkit scan. I recommend the malwarebytes free rootkit scanner for that too.
Doing all of it wouldn't hurt, but at least do those three to start.