How does the VFP System Clock get updated?

I have an app that uses timers to trigger night jobs.
I don't keep track of time using the timer, I just fire a
timer method every 10 minutes, compare TIME() with the run
times on a list of jobs (in a job list table), then run
one whose Job Time < TIME().

The problem I'm having is that something appears
to stop TIME() from updating. When I come in the next
morning the app is still running. The time reported on the
VFP status bar may be say ... 6:38pm. The time reported
on the Windows status bar is the correct time (say 8:01am).

The VFP TIME() clock dies before the scheduled start
of my jobs.

Does anyone have an idea what may be happening??