Author: Jonas Bilinkevicius

How do you find out whether a program is available ? For example, how can you 
programmatically tell whether MS Word 2000 is installed rather than Lotus WordPro? 
The OS can be Win95, 98, ME, 2000, NT4. I did not find any Win API function 
allowing to find out if a specific application exists on the machine. The nearest I 
found is the FindExecutable function but you need to pass it a document file name. 
Should I read the registry, to enumerate the currently installed applications?

Answer:

For the MS Word case, you might want to start Word in automation mode to see if its 
present. The following routine does that:
1   
2   function IsWordPresent(var IsActive: Boolean): Boolean;
3   var
4     MSWord: Variant;
5   begin
6     Result := False;
7     IsActive := False;
8     try
9       MSWord := GetActiveOleObject('Word.Application');
10      Result := not VarIsEmpty(MSWord);
11      IsActive := not VarIsEmpty(MSWord)
12    except
13      MSWord := Unassigned
14    end;
15    if VarIsEmpty(MSWord) then
16    begin
17      try
18        MSWord := CreateOleObject('Word.Application');
19        Result := not VarIsEmpty(MSWord);
20        if Result then
21          MSWord.Quit
22      except
23      end;
24    end;
25  end;