You can use QuickField command-line switch /Solve to run QuickField in unattended mode for solving a set of problems:
>"C:\Program Files\QuickField\QField.exe" /Solve "C:\My Problems\Magn*.pbm"
Please note the use of double quotation marks around the pathnames with spaces. The list of arguments may contain several items, with optional wildcards (*) in it.
There are several ways to schedule an application to run at specified time with specific set of parameters. The most convenient seems to be the Scheduled Task utility built in Windows.
You can also use third-party software for scheduling.