Does the problem go away if you take the new hard drive out and put the old one back in? Have you tried booting your computer in other ways-- from disc, from USB, from another Mac? See if you can isolate the problem to just one chip or just one slot by swapping them around. Does the drive have some pins with shorting plugs, or dip switches or some other method of configuration? The disk is stuck in there for now and not sure how to get it out since I can't reach the desktop. I will look into resetting PRAM Nope to resetting the PRAM.
imac - My Mac repeatedly beeps three times on startup. What does this mean? - Ask Different
Holding down the mouse button during boot should eject any media in the drives. I had no idea Macs had beep codes.
It's not at all clear that they still do; the most recent reference I've found to beep codes for Macs is , which could be in the lifespan of your Mac. The code indicates, pretty universally "no good [RAM] banks. Do you have a second computer on which you can test the RAM?
Know someone who does? Also, can you test the HDD using another computer; perhaps using an enclosure if not a full hardware install?
Why is My Mac Beeping When I Turn it on?
Have you tried booting without any USB devices connected? USB devices can confuse and intimidate even the heartiest and most sober of bootloaders. Have you tried booting from a Live CD? RAM is not outrageously expensive, even with the Mac premium. Get all the RAM you can afford. Good luck.
Is this 3rd party RAM? If yes, it's still probably under manufacturer warranty. I'm a full time IT director, I've returned plenty of memory due to it not meeting Apple specs. Please help me find a way to backup my files before I take it into Apple for fixing.
Backing up your drive is a good idea before taking it in for repairs. In your situation, with the Mac crashing just after startup, there are a few things I would try. If you have another Mac handy, try booting your iMac into Firewire Target mode. Then connect it to the other Mac and use that Mac to grab the files and back them up to an external drive using SuperDuper! Try booting your iMac into Safe Mode to see if it will not crash and allow you to backup.
If it is a memory problem, then try taking out one of the probably 2 memory sticks in your Mac. Three beeps that play and then stop as the computer starts successfully mean that the BIOS was restored. While some other programs may also have a three-beep sound, those that mean you need to take action and repair your computer will sound right as the computer operating system is turning on, and the tones will replay after a pause. The beeps will continue until the computer is powered off and will play again when it's on unless the problem is fixed. The first thing to do is remove any extra RAM you added to the computer before turning it on.
Once the RAM is removed, restart the computer and wait to see whether it powers on normally. If it does, try re-inserting the RAM and seeing whether you can install it more securely in the computer.