what's telling you to download Registry Mechanic 5.2?
Edit: if it is wlm or plus!
make sure you downloaded these two programs from the official pages:
windows live messenger ->
http://get.live.com/messenger/overview
plus! ->
http://www.msgpluslive.net/download/
if you did not, then uninstall the ones you have, and do a anti-virus check.
none of these should be asking you to download registry mechanic.