The most reliable method to check if your computer is a laptop is to check if it has a battery.
Try using the function: IsLaptop()

 Code:
Break On
If IsLaptop()
	'Your Computer is a portable device'
Else
	'Your Computer is a NOT portable device'
EndIf
Get $x

Function IsLaptop()
	Dim $oWMI,$cItems,$oItem
	
	$oWMI = GetObject("winmgmts:root\cimv2")
	$IsLaptop=0
	$cItems = $oWMI.ExecQuery("Select * from Win32_Battery",,48)
	For Each $oItem In $cItems
		$IsLaptop=1
	Next
EndFunction

-Erik