iMac G3 needs help

Dear friends, I need your help. I'm new to macs but I'm happy that my experience with macs starts from iMac G3! First off all sorry for my bad English - I'm from Ukraine, so please excuse me =)
I have the following problem: when I start my iMac G3 it does not load. It makes a sound like "tada..." (chime) and then display becomes grey (it is started but no text is showing). If I press and hold the button on the side with a pen (i do not know how this button is called) I receive the following screen:



Can please someone experienced person advise me what to do?

P.S. I have the CD inserted to the drive and I can not eject it. If I type "eject cd" in this menu it is thinking for a long time and does not do anything. My mac freezes. But if I type "eject abcd" for example it say that this is unknown command.

Thank you very much for your help!!

Thank you for your advise, when I'm at home I will try it.
Can you please also advise me what to do with CD-ROM? I inserted the disk and now I cannot extract it.

I will try this advise also and will let you know the result by posting in this thread. Thank you very much!!

Hello once again!
I have tried the advises and unfortunately none of them helped:
When I press and hold the left mouse button it does not eject the CD. I hear it spinning inside like a normal working CD (it fastens and slows down then fastens again. No scratchings, no stucks). I do not have the original MAC mouse so I connected the PC USB two-button mouse with a scroll. Hope it does not matter.
Also I do not have mac keyboard so I connected PC USB Keyboard, just a usual usb keyboard. Hope this does not matter too

When I type mac-boot it goes to the green screen and nothing happens later.
When I hold down the 'C' key on the keyboard it does not start loading from CD also. I can suppose that the CD is bad so I want to record a 100% working installation CD but first I need to eject the one that is in the CD-ROM already.

Please help!

By the way, when I type "eject cd" it starts thinking, I can't type anything... and then after 5 minutes it says: "can't OPEN the EJECT device"
and nothing happens after that, I can type the commands again.

Guys, this can sound incredibly but I finally ejected it. You know how? I found a very small button on the face of the cd-rom and pushed it with a pen (it is not a pinhole it is a small button) and it ejected!!
Now I burned the new installation CD. Can you please advise me how I can start the installation?
Thank you.

How to eject cd in imac G3:

Thanks everyone who participated in this thread. Hope the solutions advised here and also the solution to eject the CD physically (by pushing the eject button found) will help a lot of people who got to situation like mine.

Now I have some ther questions and they continue in another thread:
https://forums.macrumors.com/showthread.php?p=15454366#post15454366
If you want to help me - please join

Thanks all!