Hi,
This particular problem has been bugging me for weeks on my LG 32LC2DB (32" LCD TV with RGB VGA input). I know this thread is old, but for anyone still suffering this problem, I've found the cause and have a cure for it!
Basically, it's to do with nVidia video drivers. Specifically, it's related to the "Play On My" submenu which appears on the context menu whenever you right-click a video file (AVI, MPEG, or WMV). The nVidia drivers install a "context menu handler" which runs NVCPL.DLL to detect analog display devices and list them in the "Play On My" submenu. It's this detection process that blanks the screen for several seconds!
When you have a monitor as your primary display and a TV as a SECONDARY display, it's nice to have the option Play On My > TV on the context menu. It doesn't matter if the TV blanks out, because your monitor doesn't. However, when the TV IS your primary display and blanks out, the few seconds of seeing nothing but a black screen soon becomes annoying!
Solving the problem is a simple matter of tweaking your Windows registry to disable the links to the "Play On My" context menu handler for AVI, MPEG and WMV file type classes.
To make things easy, I've created one REG file to disable the links and another to re-enable them (if required). Here they are:-
Filename: nVidia-PlayOnMy_Disable.reg
<begin>
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\AVIFile\shellex\ContextMenuHandlers\PlayOnMyTV]
@=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\mpegfile\shellex\ContextMenuHandlers\PlayOnMyTV]
@=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMVFile\shellex\ContextMenuHandlers\PlayOnMyTV]
@=""
<end>
Filename: nVidia-PlayOnMy_Enable.reg
<begin>
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\AVIFile\shellex\ContextMenuHandlers\PlayOnMyTV]
@="{FFB699E0-306A-11d3-8BD1-00104B6F7516}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\mpegfile\shellex\ContextMenuHandlers\PlayOnMyTV]
@="{FFB699E0-306A-11d3-8BD1-00104B6F7516}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WMVFile\shellex\ContextMenuHandlers\PlayOnMyTV]
@="{FFB699E0-306A-11d3-8BD1-00104B6F7516}"
<end>
To save these to your hard drive, run Notepad, cut & paste everything between <begin> and <end> into it and save as the filename given.
To disable the context menu handler, right-click nVidia-PlayOnMy_Disable.reg and select Merge! Hey presto! No more blanking!
To re-enable the context menu handler, right-click nVidia-PlayOnMy_Enable.reg and select Merge. This restores things to the way they were.
Hope this helps.