If you are concerned that you might have a hacker or malware on your machine there are a number of steps you can take.
These are not something I can list out in an email as its complex and circumstance dependent. Consider that these activities are that of a specialist so you will need to learn what you are doing.
See The Complete Cyber Security Course Volume 4
Section 7 - Threat Detection and Monitoring
Section 8 - Malware and Hacker Hunting on the End-Point
An alternative is hiring a professional to do this for you.
I hope this helps.