You can display a legal notice on startup to warn users from a illegal use
of your computer
1) open registry editor and navigate to following path.
2) HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentV
ersion\policies\system
3) In right side panel you will see two entries named "legalnoticecaption" and
"legalnoticetext".
4) Just change the value you want.
5) Now Close registry editor & Restart your Computer