You do not state which Windows, that makes help difficult.

Try looking here and work through carefully. Personally I would start with item 7 the SFC program, it will likely fix the issue unless your computer is infected.

What anti virus and malware programs are you running? Have you updated those and ran a FULL scan with each to ensure the machine is clean?

Why don't we we look in the application data folder.

AppData\roaming, see whats in that folder. Like owbist said "need to know the operating system" so we can guide you to the folder location, as there different locations for each operating system.