[quote="jon"]USB versions are not "installed" or "uninstalled", they just run off the USB stick, so I'm not really sure what you've done.
However, see the FAQ on How to manually remove Explorer Replacement settings as it should let you fix the problem.[/quote]I also had this same problem. Created the portable from a x64 Win7 machine, for use in a 32 bit only environment. After running it for awhile (weeks, months), when I closed DO and removed the USB stick, My Computer, My Network places, as well as all other Explorer functions stopped working correctly. When the "Select Program to Run" popped up, the "Always Use This" was grayed out and couldn't be selected.
When you say "I'm not really sure what you've done"... I didn't do anything but run the portable x86 version on an XP machine from the USB stick. Luckily, the link you pointed to with the registry update fixed it. But this was definitely a problem and was definitely nothing I caused. The program made the changes on its own, and didn't correctly remove them when DO was closed and the USB stick removed.