Didn't this issue come up while in the Alpha testing?... on almost any Vista notebook with the 945 Express Chipset.. A new driver fixed the problem.. but because of Sony's policy to only let "approved" drivers install this was not possible by one of the testers..
This is also the same on a DELL laptop (Inspiron 640)0 using the same chipset !
Is there a workaround to install the latest driver from the INTEL website ?