$shell = New-Object -COM WScript.Shell
$shortcut = $shell.CreateShortcut('C:\Users\<myname>\Desktop\Mozilla Firefox.lnk')  ## Open the lnk
$shortcut.TargetPath = "C:\Program Files (x86)\Mozilla Firefox\firefox.exe"  ## Make changes
$shortcut.Description = "Our new link"  ## This is the "Comment" field
$shortcut.Save()  ## Save