As part of Microsoft's security enhancements, Windows now enforces a good security practice of always operating as a standard user, rather than administrator.
When you first run the Windows 7/Vista command prompt as an administrator, you will not get admin priviledges - you need to "elevate" the command prompt in order to perform administrative tasks. You can accomplish this by following the simple steps below:
1. Click the Start button.
2. In the Search box, type: Command Prompt
3. Right-click the Command Prompt icon, and choose "Run as administrator".
4. Enter the admin credentials and you are ready to go.
Note: Most Windows programs can be explicitly started with administrator priviledges by right-clicking the icon and choosing "Run As Administrator".
Shortcut: Hit the Windows key; type cmd; press Ctrl+Shift+Enter; and then Alt+C to confirm the elevation prompt. Six keystrokes to an elevated command prompt!
See Also:
How to change Windows User Account Control (UAC) settings