Trouble logging in at Darwin screen, and why am I seeing the Darwin screen?

Question

Dear experts,
Upon powerup restarting, my iMac sequences through the startup routine (through chime, apple logo, Mac OSX blue progress slider) and then...
...I'm faced with the Darwin terminal login prompt>...
...then I type in (what I think is?) my user name and attempt to type in (what I think?) is my password, but the terminal window won't accept the "@" character which (I think?) features in my password...
...then after a few seconds the machine progresses to a completely blue screen and a lonely mouse pointer. This happens irrespective of whether I try to enter a user name/password or not at the Darwin login page.
Most of the recommended fixes I've been able to find refer to insterting the original startup disk, and starting from scratch, but I can't open the DVD draw...!?
Can anyone please advise how I can fix my broken iMac?
Specifically:
1. Why is my start-up routine stopping at the Darwin screen, and then proceeding to an empty blue screen?
2. How can I open the DVD drawer (the keyboard eject doesn't work during the start-up process), given the sequence described above.
3. How can I confirm (or reset) my login/password at or before the Darwin login terminal screen.
Many Thanks in advance!
iMac G4   Mac OS X (10.3.9)   max ram, blutooth kboard/mouse, external lacie disk

Answer 1

Owning an Apple USB keyboard is nearly essential if you have a computer
with the bluetooth wireless; owning the 'best access option' is in having one.
My iMacG4 could use a BT keyboard and mouse, but then I realized I could
do other things with the cost difference and bought a spare Apple keyboard.
So, my real spare is the original new Pro keyboard; the spare mouse is the
one shipped with the computer, too. The feel of the new smaller USB key-
boards is more exact than the pro keyboards that are no longer available.
And a wired keyboard is more direct; so long as the wires or USB port and
circuit haven't failed somehow.
The Mac Pro has that fancy expensive memory; with heat sinks and so on;
but it could be a durable workhorse that should last a long time. Users of the
older models have some stashed extra parts on hand in case they become
harder to find later on in the larger product life cycle the devices are capable
of surviving. Owning more than two (with decade-long expectations) would be cheap
insurance of having some main components at some later time. The G5 dualcore
dual processor machines are rather substantial; but they ran a shorter duration
product cycle than the G3/G4 technologies. Third party upgrades are one likely
source for accessories and cards, processor upgrades, etc.
If you were to consider the older G4 DP machines, they may become
among the unsupported for later OSX+ developments and so it is a
matter of cost equalization or value over time. The Mac Pro looks like
a great winner and leaves an era behind.