CHM documents in Vista system can not be opened solution

        Windows Vista sometimes has some problems. I saw someone on the Internet yesterday asking why the previous CHM document could not be opened under Windows Vista.
Q: The CHM document I downloaded on the Internet is normally opened in the XP system, but it cannot be displayed when opened under Vista, but the directory attributes in the CHM document can be displayed normally, as shown in the figure:

Figure 1
Solution
1. Select the right mouse button on the downloaded CHM document and select Properties. Figure:

Figure 2
2, in the pop-up properties window, select unlock, as shown in Figure

Figure 3
3, open the CHM document can be displayed normally < Br>
Figure 4
4, and open the CHM document properties again, there is no option to unlock the lock

Figure 5