Can not save hosts file in Windows Vista

When you try to save Hosts or lmhosts file in Microsoft Windows Vista you get access denied error.

Work arround to this issue is specifically opening notepad as administrator even if you have logged in to computer with administrative privilages.

• Click Start -> All Programs -> Accessories -> right-click Notepad, and then click Run as administrator -> Enter administrator password if requested
• Open the Hosts file or the Lmhosts file -> make the necessary changes -> Save

http://support.microsoft.com/kb/923947