If it ain’t broke, don’t fix it. I learnt from my experience with previous update for MediaCenter. I have never seen this problem on mine, so I won’t be patching it.
For the rest of you… 
The Windows XP Media Center Edition 2005 Update for Standby Mode helps prevent the black screen that you may encounter when resuming use of the Media Center PC from Standby mode.
Download details: Windows XP Media Center Edition Update for Standby Mode
Pizza e Fichi 