GNOME cannot interfere with Ctrl-Alt-F[N], since this is caught by the kernel, which implements VT switching. I.e., those key events never reach userspace, which is why you/your DE/any DE cannot override them or use them for some other purpose.
So if you can't switch VTs, there is a system level issue. In my first comment I said this sounds like panicing/busy looping, which it does. However, having that last 8 hours is pretty weird -- my next thought is it is I/O failure. Since you are using ubuntu 10.10, I presume this is an older netbook and the problem is new, even though you are still running the same old software. You also mention the problem has happened before but perhaps has been getting more serious, which again points to (disk) I/O failure -- your harddrive is dying. This creates a very nasty, unavoidable snag if the root filesystem is involved.
Unfortunately, you won't be able to tell for sure until you can look at the system logs. Right now, even if you had sshd running, I suspect you would not be able to get in because, again, it's the whole system that's frozen.
You can try shutting down and rebooting (moral of story: save work frequently, and save to some backup medium -- cloud, usb stick, whatever -- often as well). If it really is disk failure, you may be lucky to get anything off the disk. If you can reboot, the first thing you should do is:
cd /var; tar -cjf log
Then save /var/log.tar.bz2 to something so you can look at the logs on another computer, because (once again) if it is disk failure, this one is not going to be much good until you replace it. You may be able to duct-tape the problem by running e2fsck -cc (see man e2fsck) on the partitions, but that requires mounting the disk without the system on it running (e.g., if you can boot a liveCD from the external CD-ROM).
Best Answer
Again, as I answered to this question, it is entirely up to whoever sets the system up. Normally only a limited number of
gettys are started, as people nowadays use X instead of a tty (or usescreen(1)...), starting more than a handful is waste. If you want to startgettys on all 64, feel free.The
pty(and some other exotic starting letters) are pseudottys, faked by software to run e.g.xterms and otherttyusers, in contrast to the "real"ttys (which aren't so real anymore...).