I have been quite busy, but I've looked into this thread a few times. I hadn't chimed because it looked like things were mostly under control and I didn't want to get in Fed's way.
Ivy,
When I use msconfig, I get the same error message, but it still works for me. When you were presented with the different options, did you try Selective Startup? Try going through the steps once again just to see what happens. If you're still having trouble, it may be an issue for the Windows board.
If we have to disable Comodo from startup and msconfig won't work for you, we can do it through HijackThis. But for now, when you want to disable Comodo, just right-click on its icon in the system tray (bottom right corner) and then click on Exit. Then try downloading Spybot. Also try
SUPERAntiSpyware.
Let us know if it works or if you're still having trouble.