I cannot uninstall the yahoo toolbar; because, the uninstaller requires the log file that was created when the program was installed, and CCleaner deleted it. This was a default and not an advanced setting of CCleaner.
I have ceased using the advanced settings, since CCleaner deleted the uninstall file that was necessary to remove and upgrade from IE7 beta 2.
Have you tried using CCleaner to remove the Yahoo toolbar?
CCleaner > Tools > Uninstall
If you can't uninstall it that way. I suggest that you follow the guide and post in the HJT Forum.
Good luck.
CCleaner uses the applications own uninstaller; it's like using Add-Remove Programs, so you will again be prompted for the uninstall log.
Do not press 'delete entry', as that will only remove the Registry key containing the program's uninstall string. It will disappear from Add-Remove Programs, but all of the Yahoo toolbar will still be there.
I suggest you try installing the Yahoo toolbar again, 'on top of itself'. That will restore the missing uninstall log, which, incidentally, I doubt CCleaner actually deleted.