Have to prevent - beware of Win XP's "automatic update"

        Recently, some computers with Windows XP installed when logging in, the system prompts "The product number of this media type is invalid. Please reinstall your system with the correct installation CD, error code: 0x80040509". No matter what username the user uses (including the Administrator), it will not be able to enter the desktop normally. It takes a long time to repair with the Windows XP installation CD, and the contents of the C drive of an individual computer cannot be maintained. Fortunately, using "safe mode" can enter, after research, and finally fixed this error in "safe mode". The specific method is as follows:

Step 1: When the computer starts up, press the F8 key to call up the boot menu and select “Safe Mode” to enter. Or directly press F5 to start Windows XP with "Safe Mode";

Step 2: Open "Control Panel→Add/Remove Programs" in the "Current Installer" list for the topmost "Windows XP" Hotfix..." After performing the "delete" operation, restart the computer.

Step 3: If you still can't start normally, please enter safe mode again, delete all the "Windows XP hotfix..." in the "current installer" list, and restart the computer.

Step 4: In order to completely prevent such problems, you may want to disable the "automatic update" function of Windows XP. Right-click "My Computer", click "Properties" to open the "System Properties" dialog box, click the "Automatic Updates" tab in the dialog box, select the "Close Automatic Updates..." option, and "confirm" to exit .