Comodo Antivirus Scheduled Scanning

I have Comodo Internet Security Premium v6.0.264710.2708 installed my home PC running Windows 7 Service Pack 1.

I am puzzled by Comodo Antivirus scheduled scans, ie Quick Scan and Full Scan. Both of them are not able to perform according to my schedules. However, the Task Manager does show either of these scans is performing on the background in case of an on-demand scan required.

I appreciate it much if any technical advice will be given as soon as possible.