I mentioned earlier that the default of 20 minutes on a public computer is way too long. Therefore, I recommend that you change this value to 5 or 10 minutes to provide increased protection for your system in case a user walks away from a public kiosk without logging off.
1. Run Regedit.
2. Navigate down the tree to the following key: HKLM\Software\Microsoft\SmallBusinessServer\RemoteUserPortal\
3. Right click the entry called PublicTimeOut and select Modify.
4. Enter the new timeout value you want to have and press OK.