I'm wondering if there is a problem with your Windows Task Scheduler as all these settings are doing is modifying the PCDoctorBackGroundMonitorTask Scheduled Task that we create upon install of the product.
Let try the following steps:
1. In the settings page, which is the page you took a screenshot of, go ahead and deselect the Enable Quick Hardware Scan and then click Save.
2. Select the Enable Quick Hardware Scan and click Save.
3. Try and modify the settings once more and then click the Save button.
If this does not work, I'd like you to open the Windows Task Scheduler.
A. In Windows 8 this can be accomplished in the Modern UI by moving the mouse cursor to the bottom of the screen and right clicking.
1. Next click the All Apps button.
2. Under the Windows System choose Control Panel.
3. At the Windows Control Panel Click the System and Security Link.
4. Under the Administrative Tools category there will be a Schedule Tasks link, please click it.
5. Click on the Task Scheduler Library.
B. If you do not prefer the Modern UI, in the classic Windows Desktop view move your mouse cursor to the bottom left corner of the UI and hold it there until a small representation of the Modern UI is displayed and then Right Click on the Modern UI representation.
1. A quick launch list will be presented to you.
2. Click the Computer Management link.
3. In the Computer Management click the Arrow to the left of the Task Scheduler to expand the tool.
4. Click on the Task Scheduler Library.
Once at the Task Scheduler Library confirm that there is a PCDoctorBackgroundMonitorTask.
1. If there is a task (and there should be,) you can double click on the task.
2. Next Click on the Triggers Tab.
3. Double Click on the Trigger (In your case in the trigger column which is the first to display, it should state Monthly)
4. Adjust the settings to your preference and click OK.
If there is no Task please let me know and I will help you through more troubleshooting of the issue.
Thanks,
Colin