IMac with Startup tones issue - 3 short + 3 long + 3 short

Question

Hello,
I recently acquired a 24" iMac (early 2009)model from a friend; it had been working perfectly when he had it but once I transported it to my place and set it up, its not properly booting up. The problems is:
1- On startup while the screen is still off, it gives 3 short tones, 3 long, 3 short tones, and then goes silent.
2- Then it seems like its trying to access an expected media in the DVD drive.
3- After a short while, it finally starts up but with a progress bar below the Apple icon.
4- On completion of the progress bar, it shuts down and then behaviour goes back to step #1. This loops continuously till I force it to shutdown.
I haven't been able to find anything in the support area here about 3 short, 3 long, and 3 short tone sequence. The only reference is to 3 long, 3 short, 3 long tone sequence (http://support.apple.com/kb/HT2538?viewlocale=en_US), or http://discussions.apple.com/thread.jspa?threadID=2372353&tstart=0.
So far I have done the following:
1- Reset the RAM modules - no effect
2- Used the Firmware Restoration CD 1.7 & 1.8 - No effect
3- Reset PMU - no effect
4- Upgraded from Leopard to Snow Leopard - no effect
However, when I reset the PRAM, this is the only way for the machine to start up properly. And once it does, it works fine, but on restart/or starting after shutdown it exhibits the same behaviour.
If one of the RAM modules had done bad, I would recoken that it wouldn't be able to start up at all (as per reset PRAM technique). So what could this be?
Luckily the machine is under AppleCare but haven't had the chance to call them up (due to working hours clash). So just want to see if this issue can be user fixed or is a hardware issue which would require a visit to an Apple store (quite a bit away here in UK).
Many thanks!

Answer 1

3 long tones, 3 short tones, 3 long tones Firmware restoration from CD in process. See About the Firmware Restoration CD (Intel-based Macs) for more details.
from here http://support.apple.com/kb/HT2538?viewlocale=en_US
Also seems the only update available for the 9,1 imac is related to the ATI Radeon HD 4850 Video card. Do you have this card?
See here http://support.apple.com/kb/HT1237 and here http://support.apple.com/downloads/iMac_EFI_Firmware_Update_14
This update fixes intermittent system freeze issues for iMac computers with ATI Radeon HD 4850 graphics and fixes wake-from-sleep issues in Boot Camp.
Loading the 1.7 and 1.8 firmware does not seem a wise idea.. 1.7 is for the 4,1 and 4,2 imacs, and 1.8 is for the Mac Pro (Early 2009) 4,1 and Xserve (Early 2009) 3,1
Also this symptom has been reported as linked to faulty RAM refer here http://discussions.apple.com/thread.jspa?threadID=2372353&tstart=0
Edited by: Richdave