if i answer no then i must be using ext3  for Windows 

 dat poll question has no meaning.
da 

 shuld be 
What file system u use for Windows XP ?
-> FAT32
-> NTFS
If u r da admin and u have limited user accounts on ur PC then simply select ur folder in X:\Documents and Settings--> right click and select properties-->click sharing tab-->and select make this folder private.
u can use hide folders or secure files or fileprotect to protect ur files. 
 
wait for other replies which might give u more info.