I recently upgraded my work laptop from a T410 to a W520 and I am no longer able to use the VGA cable attached to my ThinkVision L2250p. I currently have WinXP Pro V2002 32-bit SP3 and Device Manager shows my display adapter as "Intel(R) HD Graphics Family" driver version 6.14.10.5394, shows two Monitors as "ThinkPad Display 1920x1080", and under Other Devices it has a yellow question mark for "Video Controller (VGA Compatible)." 

When I use ThinkVantage Presentation Director and plug in the VGA cable to the W520 it says "Your computer is not attached to an external monitor or projector. Attach one and then select this scheme again." When I open the Intel Graphics and Media Control Panel in the system tray, it does not allow me to select multiple displays and says "Monitor/TV Settings are not supported." 

When I go to have Lenovo automatically detect my hardware (using IE only, ugh) it says I have a Nvidia Quadro 1000M card - not what Device manager says. So I tried to install that driver, but of course it failed because I do NOT have that card.

What in the heck is going on here? I just want to be able to use my monitor again. Is that going to be able to happen?

How much memory is in this W520?  Just curious.

It's got 3Gb of RAM in it.

The W520 has either a 1000M or 2000M...and external monitors on the W520 are driven by the Nvidia GPU. The machine supports Optimus display switching which indeed XP does not support.

Would recommend doing as said earlier and setting graphics to discrete, then installing the Nvidia drivers and seeing what happens.