I installed CCleaner on a 2003 machine that is our ISA server. Through version 1.26 it worked great. When I installed version 1.27 the install ran YTB.exe and then the tray icon for MSSQL Server disappeared. Since then the computer will not allow anyone to log on. I log on to it and it immediately logs me back off.

The tray icon happened with a 2000 server, but that one allows me to log on fine. Any ideas?

did you install yahoo toolbar with CCleaner? There is an option to chose at install proces! Chech that out (i think that YTB.exe is Yahoo toolbar (im 80% sure))

YTB.exe is the Yahoo toolbar.

OK, I see that now. But why in the world would that installation mess with my MSSQL server and not allow me to log on? That makes absolutely no sense to me.

I have no idea why MSSQL stopped working byt YTB.exe is Yahoo! toolbar and that is bad for you!
Get the alternative build, the "Slim" one, it dont have Yahoo! toolbar.

Also, if you into SQL, then you might look into replacing MSSQL with MySQL which is free, open source, cross-platform. It can make it easy for you to port whatever you do to other platforms and systems which makes it more useful. Also MySQL is well-known for its awesome performance, and it is used by many many websites on the Internet and many business, I think it is the most popular database server.

Yes, we also use MySQL. I don't have any decision-making power when it comes to what they decided to buy earlier

I'm not sure that MSSQL stopped working, but since installing, I have been unable to log in. It just keeps logging me back off.