http://delphi.about.com/cs/adptips2004/a/bltip0504_4.htm
When using ShellExecute (as explained in the above article) to open a web site or a htm file with the default web browser you *don‘t* have the option to specify that you want to start a new instance of the browser - in general an existing window is used.
To make sure a new window is created we need to call the ShellExecute function a little differently - by specifying the URL as a parameter to a call to your default browser (an application associated with the htm and html, etc extension).
uses Registry, ShellAPI; function BrowseURL(const URL: string) : boolean; var Browser: string; begin Result := True; Browser := ‘‘; with TRegistry.Create do try RootKey := HKEY_CLASSES_ROOT; Access := KEY_QUERY_VALUE; if OpenKey(‘\htmlfile\shell\open\command‘, False) then Browser := ReadString(‘‘) ; CloseKey; finally Free; end; if Browser = ‘‘ then begin Result := False; Exit; end; Browser := Copy(Browser, Pos(‘"‘, Browser) + 1, Length(Browser)) ; Browser := Copy(Browser, 1, Pos(‘"‘, Browser) - 1) ; ShellExecute(0, ‘open‘, PChar(Browser), PChar(URL), nil, SW_SHOW) ; end; //Usage BrowseURL(‘http://www.cnblogs.com‘) ;
How to open a web site with the default web browser in a NEW window
原文：http://www.cnblogs.com/shangdawei/p/4053792.html