Alright one last go, lets hope this works. I wrote a bat file so it would automatically insert the messenger block in your hosts file. After saving this file you should right click and 'run as administrator'. You can always right click this file and click
'edit' to view the source. http://ver.one/OutlookMessengerBlock.bat. If it works correctly you should get this.

Thinking ahead
If I accidently delete this on my website in the future here is the source.
@echo off
set path="%windir%\System32\drivers\etc\hosts"
echo # Copyright (c) 1993-2009 Microsoft Corp.>%path%
echo #>>%path%
echo # This is a sample HOSTS file used by Microsoft TCP/IP for Windows.>>%path%
echo #>>%path%
echo # This file contains the mappings of IP addresses to host names. Each>>%path%
echo # entry should be kept on an individual line. The IP address should>>%path%
echo # be placed in the first column followed by the corresponding host name.>>%path%
echo # The IP address and the host name should be separated by at least one>>%path%
echo # space.>>%path%
echo #>>%path%
echo # Additionally, comments (such as these) may be inserted on individual>>%path%
echo # lines or following the machine name denoted by a '#' symbol.>>%path%
echo #>>%path%
echo # For example:>>%path%
echo #>>%path%
echo # 102.54.94.97 rhino.acme.com # source server>>%path%
echo # 38.25.63.10 x.acme.com # x client host>>%path%
echo.>>%path%
echo # localhost name resolution is handled within DNS itself.>>%path%
echo # 127.0.0.1 localhost>>%path%
echo # ::1 localhost>>%path%
echo.>>%path%
echo # OUTLOOK MESSENGER BLOCK>>%path%
echo 0.0.0.0 ui.skype.com>>%path%
echo 0.0.0.0 api.skype.com>>%path%
echo 0.0.0.0 kes.skype.com>>%path%
echo 0.0.0.0 a.lw.skype.com>>%path%
echo 0.0.0.0 trap.skype.com>>%path%
echo 0.0.0.0 apps.skype.com>>%path%
echo 0.0.0.0 login.skype.com>>%path%
echo 0.0.0.0 api.aps.skype.com>>%path%
echo 0.0.0.0 api.mcr.skype.com>>%path%
echo 0.0.0.0 api.asm.skype.com>>%path%
echo 0.0.0.0 prod.tpc.skype.com>>%path%
echo 0.0.0.0 a.config.skype.com>>%path%
echo 0.0.0.0 contacts.skype.com>>%path%
echo 0.0.0.0 flagsapi.skype.com>>%path%
echo 0.0.0.0 static.asm.skype.com>>%path%
echo 0.0.0.0 prod.registrar.skype.com>>%path%
echo 0.0.0.0 geo.gateway.messenger.live.com>>%path%
echo 0.0.0.0 static-asm.secure.skypeassets.com>>%path%
echo 0.0.0.0 client-s.gateway.messenger.live.com>>%path%
cls
echo If this has been run as administrator your host file should have been changed.
echo Press any key to close this window.
pause