It depends on how large your drives and files are but 2 hrs to complete the scan is odd.
You may want to excude Kerish Doctor processes from your security software(s) to minimize the slowdowns.
For the info Kerish Doctor have issues running/installing in a computer system that has already corrupted or malware infected.
Otherwise KD is one of the few maintainace cum security utility that i personally recommended unlike some others snake oils programs.
How about subsequent scans after all KD processes have been excluded in F-Secure whitelist. Does the scan times improved. You may want to contact the developer for help, their support is reasonably fast and helpful.
I'll try. Thank you very much.