This is the same problem I am having with the Sony Viao, which has the SIS 651 video chip set.
So far the news is not good. I went to the SIS webpage http://www.sis.com/support/index.htm and downloaded their drivers, the video would not display.
I tried the Windows update webpage, (after deinstalling the drivers) and windows did not detect the missing driver. So that approach failed.
I will see what else I can find, but the solution may be to buy a video card for the AGP slot.