Windows Vista will move into Reduced Functionality Mode if the operating system has expired. In RFM, the operating system will deliver only the most basic functionality and only for a single hour per day. However, you will be able to gain some functionality back even if the operating system is in Out-of-Grace.
If you have failed to activate your copy of Windows Vista and the operating system is in reduced Functionality Mode, on logon you will be presented with a Windows Activation dialog box with the following message: "Activate Windows Now. Your activation period has expired and Windows is no longer working. To use Windows you must activate this copy of Windows."
The only options you will have available are "Activate Windows online now," "Access your computer with reduced functionality (This will also allow you to buy a product key online)," "Retype your product key" and "Show me other ways to activate."
Choose "Access your computer with reduced functionality (This will also allow you to buy a product key online)" and you will be right on track to regaining access to the operating system. In RFM, you will not have access to the Start Menu or the desktop items. However, you will have access to Internet Explorer 7.
In the address bar simply type "file://c:" to launch Windows Explorer. Via the WindowsSystem32cmd.exe file, with administrator privileges, you will be able to rearm Vista. Microsoft allows users to rearm Windows Vista a total of three times, prolonging the initial 30 days grace period.
If you have already passed the maximum number of times you are allowed to rearm Windows Vista then also via "file://c:" browse your way to C:WindowsSystem32Taskmgr.exe and launch Task Manager. In the Processes tab, select explorer.exe and then File and New task - Run. This will relaunch Windows Explorer, and the process will also load the Start Menu, the desktop and the taskbar. However, you will be limited to using Windows Vista in quasi-RFM mode for a single hour per day.