Deny access to files in Win XP

[DizitalNovice]

I have two queries:
1:
How can I deny access to certain files or folders in windows xp. I want some VB code or method which can prevent deletion and/or reading of certain items. Ideally, the file can be anywhere, even on a pen drive, and if I double click on it or press del, it says access denied.

2:
Can i deny access to a pen drive in a computer, in such a way that if someone wants to open it with explorer, access denied is shown, but a program on the pen drive executes and has access to the files and folders located there.

I am making a project on USB security, and that's why I need these badly.

[dheeraj_kumar]

You need to program a driver for that, and you need to do it in c++. VB can only act as a front end, and security is something thats best explored in low-level (c++) , and not highly abstracted "easy" languages like vb. Read Windows NT file system internals by Rajeev Nagar.