In fact, I already narrowed it down (in my case) to some bad interaction with the DHCP Client service. The folks at Sony were stunned when I demonstrated it to them, and quite happy. If you would go to this thread, there are repro steps to see if it's the same case as yours (my box happens to be Win7 x64 Ultimate, not XP):
https://www.mobileread.com/forums/sho...t=65074&page=2
To re-iterate what I've said before: DEP is not an answer. DEP is a mechanism to prevent programs from executing random data as if they were program instructions. If a piece of software requires an exception to DEP, something is wrong with that software.