This is generally what you are looking for. It doesn't quite work as it needs the 32 bit or 64 bit returns and I don't currently have time to input all that. My suggestion is to get a few users to return you the raw data and then you can convert it once you have a better list.

[VBA]Function fnOperatingSystem()
Dim sOSVer As String
sOSVer = Application.OperatingSystem
Select Case sOSVer
Case "Windows NT 6.1"
fnOperatingSystem = "Windows 7"
Case "Windows NT 6.0"
fnOperatingSystem = "Windows Vista"
Case "Windows NT 5.2"
fnOperatingSystem = "Windows Server 2003; Windows XP x64 Edition"
Case "Windows NT 5.1"
fnOperatingSystem = "Windows XP"
Case "Windows NT 5.01"
fnOperatingSystem = "Windows 2000, Service Pack 1 (SP1)"
Case "Windows NT 5.0"
fnOperatingSystem = "Windows 2000"
Case "Windows NT 4.0"
fnOperatingSystem = "Microsoft Windows NT 4.0"
Case "Windows 98; Win 9x 4.90"
fnOperatingSystem = "Windows Millennium Edition (Windows Me)"
Case "Windows 98"
fnOperatingSystem = "Windows 98"
Case "Windows 95"
fnOperatingSystem = "Windows 95"
Case "Windows CE"
fnOperatingSystem = "Windows CE"
End Select
End Function[/VBA]