It might be prudent for me to add a couple things to this as well. With windows 7 , often times the defragmenter will be turned on (in a schedule). If defrag runs while you are trying to render, it can interrupt the render and cause the cow to crash as well. I defrag manually. Simply turn off the scheduler. There may be other apps set within the scheduler as well, I looked at mine just a bit ago and there were a few updates scheduled on a daily basis for a few other apps I have. I deleted the schedules for those apps. :)

 My Rendo-Space 
Do you know where your towel is?! I love Vogon Poetry. :P
DON'T PANIC!

Portland Pirate Festival Arrrr!