I know how to make the program run at the certain time but how do I program it to start recording audio from the PC? (I dont want to have the PC speakers on at the time!)
Thanks
Audacity has a fairly basic but functional “timer record” feature: http://manual.audacityteam.org/o/man/timer_record.html
Then turn off Software Playthrough in the Transport Menu - See this page in the Manual: Audacity Manual
Though I deal with this by plugging in my external active speakers and turning the volume control on them right down 
WC
You need to have the audio running and you need to make sure that your Device Toolbar settings are correct for recording from the computer (make a small test recording) - then set Timer Record.
WC
One of the best forums. Thanks for the detailed and promp responses guys. This solved my problem