HelloI am using DEP ( data execution prevention ) and Norton Internet security.I am feeling that it is somethings going wrong on my computer.I try to clear check marks on some items in DEP window...after closing the DEP configuration window, and then re-opening it, i see those items are selected again!!!!screenshot is here:http://cid-2a1dc26b0896663f.skydrive.live.com/self.aspx/dep/dep.jpg

It might be cause of pirate version of Windows, if you are using non-genuine Windows , then it is the problem.I also believe that it might be cause of infection. Do full scan with following website:http://onecare.live.com/site/en-us/center/whatsnew.htm

thanks for your guide...but still the problem persist.my windows Vista Home Premium is genuine...OEM license.moreover i can not find those files via Search utility.What should i do ?is there a way to restarting this service without facing stop error?is this a important security issue? can an Microsoft Technician help me?

Yes, you could contact Microsoft Support Professional for help. Here is URL : http://support.microsoft.com/Go and look for contact support and you could contact them. Also you might be able to call to Microsoft Support Center for help. That is a bit strange that after you remove them , they get back. It might be belong to some service or software that put these there.To be more specific support for Windows Vista is: http://support.microsoft.com/ph/11732#tab12