advchk.exe is a component of Norton AntiVirus and runs as a background process on startup. It checks for any changes on your system that could have been caused by a virus. This process should not be removed since it is a vital part of your virus protection.
Non-system processes like advchk.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues