OS env for Windows

[StvB]

Hi, have wxHtmlWindow question here.

On my OnLinkClicked handler, I do the following:
---------------

def OnLinkClicked(self,linkinfo):
    f = wx.TheMimeTypesManager.GetFileTypeFromExtension('.html')
    if not f:
       return

    try:
        cmd = wx.FileType.GetOpenCommand(f,linkinfo.GetHref())
        wx.Execute(cmd)
    except:
        wxMessageBox("Something unexpected 
happened","MyApp",wxOK|wxICON_INFORMATION )

---------------

If I'm on my Windows 2000 machine at work, when I attempt to execute the 
default browser action,
 with wx.Execute,  I first get a freeze on my app ( with the About box 
showing, where I have the html
window situated). And the browser is trying to open, but instead, after a 
long delay:

"dde execute request failed: a request for a synchronous execute transaction 
has timed out"


On my XP system at home, Firefox comes up fine, and very quickly.

Main question:
I tried to add an If condition, to test for the 'OS' env variable, but this 
won't work I realize,after
noticing that *both* 2000 and XP have the value: WINDOWS_NT.

Is there any other way
of distinguishing between XP and 2000 I wonder?

Steve