How to read CBS.Log??

Here's how to read the CBS,log (be sure to follow all the steps). http://support.microsoft.com/kb/928228.

This will just tell you which files are corrupt - it wil not fix them.  To do that you either need to extreact and copy a good version of the file from the installation disk or run a repair/install (which would be my choice).  We'll need to do a system repair/upgrade using the genuine Windows Vista Installation Disk (one you own or one you can borrow from ANYONE).  Here's the procedure: http://www.vistax64.com/tutorials/88236-repair-install-vista.html.  Although this will not affect your data, settings, or programs, you should still backup your data before starting just to be on the safe side. You may have a lot of updates to re-install (including any service packs you had to remove).  If the version on the system came with SP1 or SP2 pre-installed and the disk is an earlier version, then you'll need to make a slipstream disk as follows: http://www.vistax64.com/tutorials/151606-vista-sp1-slipstream-installation-dvd.html..

Here's an article on how to uninstall Windows Live Messenger ( or disable it if you prefer): http://www.tech31.com/how-to-uninstall-windows-live-messenger.html.

I hope this helps.

Good luck!