If the asset tag is in the bios then you need a bit of WMI code to read it
Something like this:
Set objWMIService = GetObject("winmgmts:" & "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2")
Set colEnclosures = objWMIService.ExecQuery("Select * from Win32_SystemEnclosure",,48)
For Each colEnclosure in colEnclosures
strAssetID = "NULL"
strAssetID = colEnclosure.SMBIOSAssetTag
Next
If strAssetID = "NULL" then
msgbox "NO ASSET TAG SET!!"
wscript.quit
End if
' Strip out unwanted spaces
strAssetID = rtrim(ltrim(strAssetID))
Msgbox "Current Asset Tag in Bios is: " & strAssetIDstrcomputer = "."