I had Vaio Notebook which had dual VGA mode running Windows 7 Home Premium 64 Bits. Since day 1, it was randomly freeze or crash. This happened almost everyday when I turn it on. I've search thoroughly on the Net but found nothing close to my problem. Recently I found it myself, what seem the cause of the problem. It seem come from my VGA driver
on local services "AMD External Events Utility" with executable file "C:\Windows\system32\atiesrxx.exe". Since I disabled this services, my system seem to work fine until now.
Hope this help you that had the same problem till AMD release fixes to this issue.