The problem is with the graphics adapter. That is barely enough to run one instance at a decent FPS, never mind two. Also, it seems your video is using 793 MB of the system memory, so you have just a little over 1200 MB for Vista and the 2 WoW instances. I probably would try adjust that to something like 384 or 512, see if that makes a difference. But in essence the video on your laptop is underpowered for WoW.

Edit:
I found this link with tips on how to increase performance for that type of video, maybe you will find something in there that will help you out.