>Is there any way to restrict the user of the PC in accessing the contents of the PC. It aims to restrict the user from launching windows explorer, my computer through shortcut in desktop and running it run program.

You should investigate the Zero Administration Kit available from Microsoft; it allows a wide range of control over exactly what OS features are available to a user based on sets of administrative policies.

This is an effective option under NT-family OS products (NT, 2K, XP) but can be circumvented fairly easily under Win9x - there's no real security under Win9x given the ability to drop into Safe Mode and circumvent login/password entry by cancelling out of the Windows login dialog.