Thus, I refuse to use Sandboxie! Thus, for someone's PC, I decided to lock out the administrator account and installed Sudo for Windows. And made a registry entry for a new context menu, which is called "Run as administrator", thus Windows XP acts like the Windows Vista security model, minus UAC. The user will run on a restricted account. I tested it with JKDefrag, JKDefrag appears to be fine when you right click the new "Run as administrator". When you right click "Run as administrator" in the limited account, the application gets administrator privileges.