that issue is because you will need to re-install the live messenger as to
muneem and
Myth? said. the reason why is because either your pc is infected (spyware) or the files with in the live m meaning the Services for the messenger are corrupt and will need a fresh install, this occurred to me before believe me just re-installing it will do the trick

if this don't help let me know
here is one of the files that may be corrupt you can re-register it like this :
Code 80040154
►Cause: MSXML library may be corrupted and may have to be reinstalled
►Solution
->Step 1. Re-register msxml3.dll
- Click on the Start menu, select Run and type the following:
Regsvr32 %windir%\system32\msxml3.dll
Hopefully, you will see a window popup that says: DllRegisterServer succeeded in C:\Windows\System32\msxml3.dll is succeeded.
->Step 2. Restart your computer and sign into Messenger again
►anyway check your firewall and antivirus settings and include MSN into their exceptions
►check your computer clock! time and date have to be correct !