Vista - Recording Video Screen Times Out

Hi,

I do not have a video card in my computer, but the computer is new and would
allow one if necessary. I have been recording an internet seminar on our DVR
from the output of our CPU, but the computer window goes black after ~20 min.
The sound continues to record, but I can no longer see the picture. I need to
see the video portion. How do I prevent this timing out without having to sit
by my computer and wake it up every 20 min. I cannot seem to find the
settings for this.
--
DianeOR6