http://www.winnetmag.com/Article/ArticleID/13762/13762.html
This link says that
To undo this conversion run Dmunroot.exe which will revert boot and system
partition back to basic but all other volumes will be destroyed.
Alternatively you should backup any data on the disk you wish to preserve,
then delete all partitions - that should activate the menu choice "Revert
to Basic Disk", the entire disk HAS to be unallocated or free space.
Dmunroot is an unsupported utility available from Microsoft.
Subbu
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