If you lose the CD jewel case for NT, you also lose the CD Key printed on it unless you've written it down somewhere (OK - early senior moment, where did I write that down?). This is a problem when you need to reinstall.

• The CD Key is digits 6 through 15 of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProductId.
• Using Windows NT Diagnostics, the CD Key is digits 6 through 15 on the fourth line of information on the Version tab.

Meat and potatoes for NT workstation support.