Your Google search should have revealed that RaRegistry.exe is the Ralink Registry Writer. Ralink is a manufacturer of, among other things, chips that are used in wireless network adapters.
Your IBM laptop probably had a wireless adapter that used a Ralink chip and your HP laptop does not. I'm not sure of the exact function of RaRagistry,exe, but it's probably part of (or all of) a utility that can be used to configure your wireless adapter if you choose to use it rather than Windows WZC.