bootcamp win xp, external monitor won't wake after a long time

I am hoping someone can help me with this, I have seen a few similar threads but nothing that deals with my exact problem.

I have a late-2009 macbook, running xp sp3 in bootcamp. I have an external (Benq) 24" monitor set up as the primary monitor when it is plugged in, meaning the taskbar etc are all on the 24" screen and the laptop display is just an extended desktop.

Everything works brilliantly, but I tend to leave the computer for hours at a time, processing this, downloading that etc. The screensaver kicks in after 5 minutes, and the monitors turn off after an hour. If I move my mouse in the period between 5 minutes and an hour the screensaver disappears and both monitors go back to normal.

However, if I leave the computer more than an hour (both monitors have turned off) and come back and move the mouse, only the laptop display wakes up, the external (Benq) display does not. Turning that external monitor off and on again causes it's light to turn green while it searches for a few seconds and decides that there is "No Incoming Signal". The problem is, for some reason the computer still thinks it's sending signal to that external monitor, because my main desktop, taskbar, icons windows etc are all "hidden" behind this big black screen.

I can move the mouse pointer onto the laptop display like normal, and move it around, but moving it back to the main display it is "hidden" behind this massive black-ness. I can access the right-click menu on the secondary monitor, but of course any Properties or NVIDIA Control Panel windows by default show up in the middle of the main display, so I cannot see them.

The only workaround I can find other than unplugging the external monitor and plugging it back in again (which means I have to go through the entire "configure external monitor" process again - takes a good 10 minutes to set everything as I like it) is to close the laptop display so the computer goes to sleep. then open it again and Lo and Behold both monitors wake up properly.

Is there any other way to force the graphics card to re-recognise the external monitor and start sending it a signal again?

Sorry for the verbose post, I tend to run on a bit...

This is likely a problem with the nVidia driver. You may be able to update the driver by going to the nVidia site and downloading the latest Windows XP driver for that particular chipset. It might cure it, it might not.

Or you can try running your MacBook in clamshell mode instead of extended desktop and you should not have that problem. Of course that means the 24" monitor is your primary monitor and the internal display of the MacBook will remain off.

Just to let you know, I had the same problem here with an older MacBook that uses an Intel chipset. Updating the driver (downloaded from the Intel site) cured it. But I generally run my MacBook while at home in clamshell mode. In other words, I use it as a desktop.