I read about this tweak a long time ago and even found out couple of ways of achieving the same results but wasn't sure of the importance. But you know what, there is reason for everything. Assume your are working on computer where you don't really own the computer or is shared with someone else. Do you want maintain privacy and avoid other know what you were doing etc. Then this tweak may be of interest to you. Go to Control panel Administrative tools, local security policy. Then goto local policies ---> security options.Then change the option for "Shutdown: Clear Virtual Memory Pagefile"