i believe that many people install more than one windows systems in one computer machine for their specific usage. but how can control one system is unable to access the other system resource (including hard drive whole partition, whole NTFS partition, all folders and all files) or one system only can access the other system openned folders and files.this is never made before in windows system I believe. this function can issolate virus broadcasting from one system to the other in same computer machine. And also, this function can protect anyone personal information in their own windows system from the others. I hope windows system 7 can add this great function into it to let system stronger and powerful.

If I understand you correctly Windows 7 already does this.If you install WIN7 in dual boot then the partition with the other OS will be hidden.

Sorry but this is wrong win7 in a dual does nothing to hide the other partions or anythingI run portable apps from a share on C:I run those apps in both XP and win 7 on the same systems

I have dual-boot XP SP3 and 7 7100 build series.When I boot with XP, I cannot access or even see partition on which I have installed Windows 7, even in Disk Management.When I boot with WIndows 7, I am able to access partition on which I have installed XP.