I was modifying a VB6 application to include a button that launches a browser to navigate to a URL. I wanted to use the default browser and open the link in an existing window, if one existed. This was accomplished easily with the ShellExecute API command.
First, you need your API function declaration in a code module:
Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" _ (ByVal hwnd As Long, ByVal lpszOp As String, _ ByVal lpszFile As String, ByVal lpszParams As String, _ ByVal LpszDir As String, ByVal FsShowCmd As Long) _ As Long
Then you can use the API to open your URL, like so:
ShellExecute 0, vbNullString, "http://adamprescott.net", vbNullString, vbNullString, vbNormalFocus