T7500 display driver stopped responding

Hoping someone can help.

We have a new Precision T7500 running Windows 7 Enterprise 32 bit with NVS420 video card. When I was setting up the machine I downloaded and installed the drivers for this machine using the driver on Dell's website. The machine was running fine as I was setting up other applications and testing them on a single monitor.  It wasn't until we connected two 22" displays to the system that we started having issues with the "190.38 display driver stopped responding and has recovered". 

It seems to happen mostly when moving applications from monitor to monitor or stretching across two monitors. I removed the video driver that I used from Dell's web site and installed the latest drivers from Nvidia's site and that seemed to make it worse. Dell has replaced the video card but still have the same issue.

Thanks