How to limit guest user from accessing folder or harddisk

[Guest]

My Operating System is WinXp Pro
I want to limit guest user(Other user that beside Administrator) from accessing folder or harddisk by without convert harddisk to NTFS format(In Fat32 only)
If that is no way but to convert from Fat32 to NTFS , during the converting process, will it destory the data in harddisk after convert from FAT32 to NTFS?

 

[Guest]

this is how Doug Knox MS-MVP recommends to convert, and if he recommends it, I guess it does not destroy your files, BUT I DID NOT TRY IT

"CONVERT X: /FS:NTF

Where X: is the drive letter you wish to convert. You may also want to see http://www.aumha.org/a/ntfscvt.htm to ensure that you're getting the optimal conversion

After this step is completed and you've rebooted the computer, if necessary:"

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