Win7 can't open chm file solution tutorial

1. Right click on the CHM file and select Properties

2. Under the General tab, there is a “Security” button, click the [Unlock] button. Skip if there is no such button.

3. If there is no [Unlock] button, copy the following into Notepad, and then click [File] > [Save As].
REGEDIT4 [HKEY_LOCAL_MACHINESOFTWAREMicrosoftHTMLHelp] [HKEY_LOCAL_MACHINESOFTWAREMicrosoftHTMLHelp1.xHHRestrictions] " MaxAllowedZone " = dword: 00000003 " UrlAllowList " = " " [HKEY_LOCAL_MACHINESOFTWAREMicrosoftHTMLHelp1.xItssRestrictions] " MaxAllowedZone " = dword: 00000003 " UrlAllowList " = " "

4. Save as a .reg file and double-click Import.