Media center automatically starts the computer from standby

I've had a problem that I have finally found time to solve. I have a windows media center machine at home connected to my tv set. At night I put the machine in standby and every morning it start by itself at around 7. This is rather annoying since I don't have any scheduled jobs or recordings at that time.

I checked the event log and one of the first logs after startup in the application log was an 'Event Info: Guide Successfully Downloaded'.
Perhaps it's the EPG download that forces the machine to start? Can this be configured to another time in the day?

I checked the settings in mce but no entry states when to download the epg. So after some googling I found a post in one of the The Green Button forums that took up the issue.

To cut it short, the user Cowboy found out that there are two registry keys controlling this behavior

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Media Center\Service\EPG\dlLastTime

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Media Center\Service\EPG\dlRegTime

These keys contain the date when the guide was downloaded the last time and when it is registered to run the next time. The data format is stored in NT Time Epoch format but backwards. (see Cowboys forum post for detailed information)

To fix this you can set these values to another time and date by updating these registry values and restart the computer. For ease of use riesm had posted an application that provides a nice GUI for setting the download time. After using this and restarting the computer is not autostarted every morning at 7.

Thanks to Cowboy and riesm for providing the great community support.