Currently Being ModeratedMar 5, 2013 8:25 PM (in response to gerowen)
Your 1) and 3) : You may need to buy or borrow an Apple keyboard to do this, but try booting while holding SHIFT. That's a safe boot that disables most extensions and does some boot volume checks. Macs have a lot of startup keyboard commands and some require an Apple board. As I have enough Apple boards to service our stable of Macs, I've not had occasion to try safe-booting a Mac from a non-Apple board.
If you get a stable desktop with a safe boot, immediately try a regular restart to see fi the disk check cleaned up enough dreck to allow a start.
Your 2 )a: Press and hold the mouse button during startup, If there is a disk in the drive, that should open the tray. Later Macs require the computer to be on wall power for manual eject to work.
Many 1.25Ghz eMacs have near-fatal logic board issue due to bad components that affected more computer makers that just Apple. Yours is not in the serial number range that was published, but affected computers have been reported outside the range. The problems, once covered by a now-expired repair extension program, are too expensive to repair on such an old computer. You can take a peek in the RAM door on the bottom of the case. It MAY show affected capacitors indicating others have probably failed. This image shows leaking capacitors visible through the RAM door,
[click image for larger view]
If you see this, I'd recommend not putting any more time into this computer.eMac 1.42Ghz, Mac OS X (10.4.11), 1.25G RAM + eMac 700mHz 768MB RAM