Is there a (more than a terminal) desktop environment/distro that can be run using only a keyboard - I have an old computer on which I cannot use a mouse - the PS/2 port is broken and it won't accept USB
I recommend using Xmonad with Dmenu, this works using shortcuts and is basically a window tiling system, it also has a very small footprint when it comes to resources, perfect for old machines.
Have you tried all the USB ports? Also, have you tried looking in the BIOS to see if it might be disapbled? If it has USB, it's hard to believe that all the ports are broken, although something may have blown it out in the past.
That said, I think you can do it, but it might be painful. It would depend on what system you're using. For mine (Ubuntu with Gnome), there is a setting under "Universal Access", in the tab "Pointing and Clicking", for "Mouse Keys" that enable you to use the keyboard.
I've head that X-Windows has a way using Ctrl-Shift-Numlock, but that doesn't do anything on my system.
I believe KDE has a setting under the mouse control panel called 'Move pointer with keyboard (using the num pad)’.
You might want to take a look at ratpoison.
Ratpoison is a simple Window Manager with no fat library dependencies, no fancy graphics, no window decorations, and no rodent dependence. It is largely modelled after GNU Screen which has done wonders in the virtual terminal market.