Sometimes it is necessary to get the OS from the user via Lotus Script. This can be done very easily:

The following button would allow you that (you can modify the code so that it fits your needs):

Sub Click(Source As Button)

Dim evalu As Variant
evalu = Evaluate(|@Platform([Specific])|)
platform$ = Join(evalu, " ")
Msgbox platform$

End Sub

If you prefer Lotus Formula then try:

@Prompt([Ok];"OS Plattform";@Implode(@Platform([Specific])))

The following can be expected then:

Windows 7 will return -> "Windows/NT 6.1"

Windows 8 will return -> "Windows/NT 6.2"

For more infos about the NT Version check wikipedia.