Nearly forgot: add the .CHM to the PuTTY installer. This involves

making the manual shortcut in the Start menu point to one or other
of the two help files depending on the version of Windows;
fortunately Inno Setup has no difficulty doing that.

[originally from svn r7028]

windows/putty.iss

@@ -48,6 +48,7 @@ Source: "pscp.exe"; DestDir: "{app}"; Flags: promptifolder replacesameversion re
 Source: "psftp.exe"; DestDir: "{app}"; Flags: promptifolder replacesameversion restartreplace uninsrestartdelete
 Source: "plink.exe"; DestDir: "{app}"; Flags: promptifolder replacesameversion restartreplace uninsrestartdelete
 Source: "website.url"; DestDir: "{app}"; Flags: restartreplace uninsrestartdelete
+Source: "..\doc\putty.chm"; DestDir: "{app}"; Flags: restartreplace uninsrestartdelete
 Source: "..\doc\putty.hlp"; DestDir: "{app}"; Flags: restartreplace uninsrestartdelete
 Source: "..\doc\putty.cnt"; DestDir: "{app}"; Flags: restartreplace uninsrestartdelete
 Source: "..\LICENCE"; DestDir: "{app}"; Flags: restartreplace uninsrestartdelete
@@ -55,7 +56,10 @@ Source: "..\README.txt"; DestDir: "{app}"; Flags: isreadme restartreplace uninsr
 
 [Icons]
 Name: "{group}\PuTTY"; Filename: "{app}\putty.exe"
-Name: "{group}\PuTTY Manual"; Filename: "{app}\putty.hlp"
+; We have to fall back from the .chm to the older .hlp file on some Windows
+; versions.
+Name: "{group}\PuTTY Manual"; Filename: "{app}\putty.chm"; MinVersion: 4.1,5.0
+Name: "{group}\PuTTY Manual"; Filename: "{app}\putty.hlp"; OnlyBelowVersion: 4.1,5.0
 Name: "{group}\PuTTY Web Site"; Filename: "{app}\website.url"
 Name: "{group}\PSFTP"; Filename: "{app}\psftp.exe"
 Name: "{group}\PuTTYgen"; Filename: "{app}\puttygen.exe"