I think you can press "I" just before the services start to get into interactive mode. Then you can select Not to start CUPS to get to the desktop to debug.
If that doesn't work, try pressing Control+C when it hanags at CUPS.
If even that doesn't work, boot into a live-cd (like Knoppix), get to the desktop, mount the / partition and edit the runlevel for CUPS (this is not exactly Newbie friendly option).
|