avgregcl.exe is a process belonging to Grisoft's Itnernet Security Suite which assists in operating system restoration after a malicious process attacks. This program is important for the stable and secure running of your computer and should not be terminated.
Non-system processes like avgregcl.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