The situation I have here is related to a brand new dell machine with a GTX260 video card. Put simply after one user logs in when that user either 'switch users' or 'logs out' windows goes to a black/blank screen. The TV screen that is used with this computer previously functioned fine with fast user switching on an XP machine. The new computer is windows 7. The TV is not outputting any error messages like 'no signal' or anything else that would be displayed if the computer was off. You can fix the problem by cycling the input on television, after cycling the input the welcome screen appears as normal.
What I want to know is what on earth is windows doing that would cause the video card to stop sending the same signal to the monitor when the user logs off or switches users. I mean as far as I can tell the resolution is identical between windows and the welcome screen. Or perhaps if somebody has experienced this before a fix would be great too.