is there exist windows API ?

From C#, you could play around with System.Directory.AccessControl, and more specifically with DirectorySecurity.
If you want to kick down to the windows API, start at SetSecurityInfo. (not for the faint of heart).
Be careful when you use these. Keep a recent backup of your system handy, as messing around with security descriptors may render your system inoperable.

Please don't push 'answer' if you're asking more questions. Edit your post. C# is not a suitable language for an anti virus program. I also don't understand the number of people who think they can single handedly write a useful version of such a project, when they get stuck on the most basic things.

Hi,

There is any other way to get access to "system volume information" folder.i am using admin account but all techniques fails.i am making an anti virus for this purpose i have to scan this folder.I also know that may it work on implementing it as a filter driver but i am unable to implement.i did't know how to implement it in c#.

Please help me if you can....

Thanks

To my knowledge, there is no way to set folder and file permissions from within an application: the risk for abuse is simply too great.