Vista - Windows Live Messenger and Windows Installer popups

Recently, I've been facing a little problem with Windows Live Messenger 9.0
beta version. Everytime I launch WLM, the Windows Installer window will popup
and show a progress bar running (meaning it's running something, I guess).
Even though WLM will run as usual after that, I don't find this normal as I
don't face this problem with WLM 9.0 beta version before reformatting.

A check in the Application logs of Event Viewer shows the following:

Event Type: Warning
Event Source: MsiInstaller
Event Category: None
Event ID: 1004
Date: 5/26/2008
Time: 9:47:06 PM
User: WONG\Wong Family
Computer: WONG
Description:
Detection of product '{F1E17FB0-12BC-45D0-ABA3-287F2A1E3A1E}', feature
'MsgrFeat', component '{7CBC9E83-5D64-4EB3-847B-E628ADDA3D1E}' failed. The
resource
'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\InstallationDirectory' does not exist.

In fact, I get a couple of the same error message shown above. I kept
wondering why, but by taking a look at the description, I think this may have
something to do with the Windows Messenger or the Messenger Service. Before
installing WLM 9.0, I have indeed uninstalled Windows Messenger using the
command, "RunDll32 advpack.dll,LaunchINFSection
%windir%\inf\msmsgs.inf,BLC.Remove" (without the qoutes), and also disabled
the Messenger service in "Services.msc" under the Administrative Tools.

In addition, a check in the registry (according to the Event log above)
shows the following: -

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService]
@="Windows Messenger"
"InstallationDirectory"="C:\\Program Files\\Messenger\\"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\Clients]
@=""

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\Clients\MSN Messenger]
"MessengerGuid"="5C4C8078-24CF-4c71-B05E-8B1D935DB5AC"
"MessengerPrivateGuid"="762DAFB9-15BD-4b41-B919-F3D5023D1E78"
"MsgrSessionManagerGuid"="A3E84F97-4A68-4e42-9976-DA8DF946B571"
"isDotNetProvider"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\SessionManager]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\SessionManager\Apps]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\SessionManager\Apps\{1DF57D09-637A-4ca5-91B9-2C3EDAAF62FE}]
"Name"="Whiteboard"
"Path"="\"C:\\WINDOWS\\system32\\rtcshare.exe\""
"URL"="http://www.microsoft.com"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\SessionManager\Apps\{56b994a7-380f-410b-9985-c809d78c1bdc}]
"Name"="Remote Assistance"
"URL"="http://www.microsoft.com"
"Path"="C:\\WINDOWS\\system32\\rcImLby.exe"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MessengerService\SessionManager\Apps\{F1B1920C-6A3C-4ce7-B18C-AFAB305FD03D}]
"Name"="Application Sharing"
"Path"="\"C:\\WINDOWS\\system32\\rtcshare.exe\""
"URL"="http://www.microsoft.com"


So, I think this may have something to do with Windows Messenger. Anyway,
can you offer any help to solve this problem?