解决几个朋友的问题
（引用自百度）
和微软的安全更新 896358有关。把chm文件改成英文文件名，问题解决……
下面是微软的支持文档。
http://support.microsoft.com/kb/892675
Example 2: Use the MaxAllowedZone entry to enable a security zoneWarning The MaxAllowedZone entry enables all sites in a particular zone. Using the UrlAllowList entry may be safer. If you must use the MaxAllowedZone entry, set the value no higher than is required. If you set the MaxAllowedZone value to 3 or higher, you expose systems to attack from the Internet.
Note By default, the value for the MaxAllowedZone entry is set to zero. The following table summarizes how different entries are interpreted by the value for the MaxAllowedZone entry. MaxAllowedZone Local Machine zone Local intranet zone Trusted sites zone Internet zone Restricted sites zone
0 Allowed Blocked Blocked Blocked Blocked
1 Allowed Allowed Blocked Blocked Blocked
2 Allowed Allowed Allowed Blocked Blocked
3 Allowed Allowed Allowed Allowed Blocked
4 Allowed Allowed Allowed Allowed Allowed
Paste the following text in a text editor such as Notepad. Then, save the file by using the .reg file name extension. This .reg file lets all content in the Intranet zone host the HTML Help ActiveX control.
REGEDIT4
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp.x\HHRestrictions]
"MaxAllowedZone"=dword:00000003
"UrlAllowList"=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp.x\ItssRestrictions]
"MaxAllowedZone"=dword:00000003
"UrlAllowList"=""
还看到另外的回答
这是一种帮助文件
用Microsoft® HTML Help Executable 打开，就是C:\windows\hh.exe 系统自带的,你肯定是把这个文件给删了。
到别人的电脑上copy一个hh.exe ，放到上面那个目录里，再双击一个chm文件，如果让你选择程序的话就选那个C:\windows\hh.exe ，这样就恢复了chm文件和hh.exe的关联了
是XP系统的问题。这个问题的发生，是由于hhctrl.ocx的版本号出现错误或未正确注册。
原因在于安装的其他软件用hhctrl.ocx的旧版本替换了原来的版本。
注册的方法是：
开始--运行，输入regsvr32 hhctrl.ocx
之后出来一个注册成功的对话框，确定
然后重启系统。
