M17X Lock up while using HDMI

I have a m17x with dual nvidia gtx 280m's running in SLI.  While using my computer, I will use an external monitor that is connected through HDMI.  Every time that I would do this, I ran into no problems; however, I just recently updated the drivers for the video cards for the first time since the summer of '09.  After updating the drivers, whenever I use the external monitor the computer will randomly lock up.  When the lock up occurs the screen will either leave the image that was there or  leave screen tearing across the monitor.  It will occur at random when doing almost anything such as playing World of Warcraft, while playing the standard OS chess game, or even surfing the internet.

I first thought the problem could be driver related.  I restored the computer to the way it was when shipped and tried it with the drivers that had worked before only to find the same problem.  Still thinking it might be driver related, I downloaded a program that would remove any driver for the video cards and cleaned it all out and reinstalled the latest drivers.  Same problem existed.  After this I thought it could be related to the computer overheating.  I stripped the computer and made sure no dust lingered in the machine and the problem still occurred.  After cleaning out any dust, I thought that maybe the drivers somehow changed the fan settings and was not allowing sufficient cooling.  I downloaded a temperature monitoring program to make sure the temperatures were remaining normal.  The lock up that occurred while surfing the internet happened when the CPU was around 30 degrees Celsius and the GPUs were around the 40 degree mark.  I then ran Warcraft on the laptop monitor for an extended period of time to make sure that the lock ups did not occur all the time and was somewhat relieved to find that the computer did not lock up.

Unfortunately, the warranty on the machine has run out and I have found no information about this issue online.  If anyone has any insight as to what could be causing this, please let me know.

Lastly, I apologize for the long post.  Being a first time poster I wanted to make sure I did not leave anything out.  If I did miss anything, let me know and I will try and fill in the missing information.

Thanks in advance for any help =)