This trick is for all those people who wants to hide tons of data into their box. So here it is, if you have very important data in your hard drive placed in some partition which you do not want anybody to see then this trick is only for you!!!
1. Just click on start>run type gpedit.msc
2. Now navigate through user configuration> administrative templates > windows components> windows explorer
3. Double click on “Hide these specified drives in My Computer” modify it accordingly.
4. Then just below you will find another option “Prevent access to drives from My Computer”, double click on this option and modify it accordingly.
5. To make it visible again select "disable" by double clicking on the “Hide these specified drives in My Computer” option.
WARNING:Don't try to experiment with other options in gpedit.msc if you don't know, what exactly your doing. Just have some patience and follow my tutorials regularly, i am going to tell you everything that is configurable in windows [and those also which you thought before, "Seems not possible to change ;-)" ].
Courtesy : http://mrsupport.blogspot.in/