Siemens MP277 touch screen system is set password so resolved?

An operation is to use the Siemens MP277 touch screen machine, the system is set password! Want to re-enter the program, but the transmission has been changed, pass not go in, want to go in to modify the transmission but can not get in, I do not know if there is no universal password? Or how to restore factory settings?
Re: Siemens MP277 touch screen after the end of the OS update your program is gone, all in your OS update (restore factory settings) to ensure that you have an active backup program.
OS update method is as follows:
1.HMI device power, good hardware communication connection, and in the control panel to set a good download path.
2. Select the menu command “Project → Transfer → Communication Settings” in WinCCflexible of the configuration computer.
This will open the Communication Settings dialog box.
3. Select the HMI device type.
Set the connection parameters.
5. Click “OK” to close the dialog box.
6. Select the menu command “Project → Transfer → Update Operating System” in WinCC flexible.
7. In “Image Path”, select the folder containing the HMI device image * .img.
The HMI device image can be found under “WinCCflexibleImages” in the WinCCflexible installation folder,
Or on the appropriate WinCCflexible installation CD.
8. Choose “Open”.
After opening the image file, the HMI device image file version information is displayed in the output area.
9. Select “Update OS” in WinCCflexible to run operating system updates. Follow the instructions of WinCCflexible. A status view appears indicating the operating system’s update progress.
OS update requires MP277 power-on time is more stringent, you can try several times, appear immediately after power-on boot, almost at the same time, it is best to find someone to assist with the update process does not turn off the anti-virus software and firewall.
Precautions:
This update requires MP277 power more time, you can try several times, appear immediately after power-on boot, almost the same time, it is best to find someone to assist.