Write-protecting.

Always write-protect your systems and program disks. 
By write-protecting these disks, you prevent anyone from tampering with them. Write-protecting also prevents disks from becoming contaminated with a virus. Write-protect tabs are easy to use and highly effective.

Access Manager - More info

     If the above options do not provide enough security for you, download Access manager for Windows.

Access manager provides much more security than standard ways in Windows.

More info

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