Device Manager
 

My system is XP Pro SP3. The problem I have is regarding the "Device Manager". I am unable to view "Non-Plug and Play drivers" even when I click "View", "Show Hidden Devices". And yes I have Clicked "System Properties", "Advanced", "Environment Variables", "User Variables" and "System Variables" with entries of "devmgr_show_nonpresent_devices" with variable value of "1". This problem has just occurred recently after installing and uninstalling various firewalls and anti virus programs. Just a footnote I am logged in as "administrator". If someone can help me out with this problem it would be much appreciated.