I recently tried to burn a video DVD on my Media Center 2005 system. I tried to fit 2 hours of recorded TV content on the DVD, and Media Center told me it would need to compress the content in order to fit it on the DVD. I pressed OK and left my Media Center going overnight to burn the DVD for me. Then, when I came back in the morning I found an error message stating that my system was out of disk space. I have my system configured with a 10 gigabyte C drive where I installed the Media Center OS and and then a 200+ gigabyte D drive where I store my music, photos and recorded TV.
After some further investigation, I found that the Sonic DVD burning software that is included with Media Center uses the default temporary folder (%temp%) when it transcodes recorded TV to compress it for burning to a video DVD. In my case, I only have about 2-3 gigabytes free on my C drive, but I have 150+ gigabytes free on my D drive. I found that I was able to change the default temporary folder location that Windows uses in order to allow my Media Center to use the D drive for temporary storage and correctly burn my video DVD.
Here are the steps I used to change the default temporary folder location and fix the Media Center video DVD burning issue I was running into:
Click on the Start menu, choose Run and type sysdm.cpl
Click on the Advanced tab and click the Environment Variables button at the bottom
Double-click on the User variable named TEMP and change it to a path on your D drive
Double-click on the User variable named TMP and change it to a path on your D drive
Double-click on the System variable named TEMP and change it to a path on your D drive
Double-click on the System variable named TMP and change it to a path on your D drive
Click OK to officially change these environment variables
Restart your computer so that Media Center will pick up the changes to these folder locations
Try to burn your television show to a video DVD again