re: my earlier posts about this problem ... my T61p has the Quadro NVS 140m chipset. I want to use a video card in the dock to attach at least 2 external monitors. It suddenly dawned on me that I was actually able to make this work soon after I got the T61p, about 3 years ago. Same dock, same Nvidia GeForce 7200gs x16 video card. Using Win XP in this original configuration.
So, what changed? Well, for one, I upgraded the bios. With the "upgraded" bios and a newer add-on video card, the machine generally refuses to boot. and instead gives post error (1 long beep, followed by 2 short beeps). The OS is never started. With the older card, the OS boots but does not load the drivers. And, of course, that's the 2nd part of the problem. The T61p has recently been upgraded to Windows 7, and it's my understanding that you can't mix drivers in Win 7. If you have 2 video cards you need to move to a driver that supports both. Further, I understand that Nvidia says you can't mix Quadro and GeForce cards in the same system in the Win 7 (and Vista) environment. Nvidia has recently released its 257 driver for Win 7 which now supports a huge array of cards and chipsets, going all the way back to the 6k variety. I can confirm that with the 257 driver I am able to use both a 6200 pci card and a 9500 gs card together, in another Win 7 system.
So, to net it out ... for my T61p situation I believe I'd need to find a Quadro add-in PCIe card which can use the same driver as the built-in 140m chipset demands, and downgrade my bios to something closer to the original version.