iMac stuck on gray screen at start up

Hello,

I am having an issue with one of my computers. It's an iMac. I'm not sure if it was running Leopard - however, after a week of acting normal, it has decided to not start up.

I get a gray screen with an apple log.
I get the chime.

I have tried disconnecting everything but the keyboard, disconnecting & reconnecting the power cord and using a different outlet
I have tried a smart boot
I have tried resetting PRAM

When I did the smart boot, I did it so I could view the black and white start up screen and it got stuck on a line that said "DNS_Server_msg invalid memory"

At this point I don't know what else to do. I don't have the Leopard OSX disc to boot from anymore. I am wondering that if I go and buy or borrow one, what the odds of it booting from the disc being successful would be? At this point I'm even okay with erasing everything on the HD, I just want to get it working again. Buying a OSX disc would cost less than taking it to the apple store or elsewhere for repair and with that being said, I'm pretty sure I lost track of how much space was full on it and I would think erasing everything might help but I don't want to buy a disc -- have it get stuck in there or not work or something and still have to pay a person to fix it. Any advice? Thanks

G'day and welcome to the forums.

Without the disc you are very limited. Also helps if you tell us what iMac as there are many dozens of models. If it is an Intel model lash out $20 and purchase Snow Leopard OS X.6 from Apple Online only and run Disk utilities options, Repair Disk, etc, when booted from the DVD.

harryb2448 said:

G'day and welcome to the forums.

Without the disc you are very limited. Also helps if you tell us what iMac as there are many dozens of models. If it is an Intel model lash out $20 and purchase Snow Leopard OS X.6 from Apple Online only and run Disk utilities options, Repair Disk, etc, when booted from the DVD.

Click to expand...

Thank you. I couldn't find the EMC on the boot but the model number' s A1173, so it looks like snow leopard might work. These are the specs I found:

iMac "Core Duo" 1.83 17-Inch Specs (Early 2006, MA199LL, iMac4,1, A1173, 2104) @ EveryMac.com

Yes it will run Snow Leopard and that is the final operating system alas as it is a 2006 model. Contact Apple Online. Suggest you make a backup of Leopard to an external drive using SuperDuper or CarbonCopyCloner, pop in the Snow Leopard DVD, reboot and holdd own 'C' after the chime, into Utilities > Disk Utility > Erase and format Mac OS Extended (Journaled) and into Partition > Options and ensure GUID is selected.
Install Snow Leopard, update to OS X.6.8and then use Migration Assistant in Utilities to drag things from the clone.

If the OP is going to "nuke & pave" the original boot drive volume anyway, I'd suggest using the option to zero out the drive when doing the erase.

That old drive is probably failing and has bad blocks which the zero out option will map out so that they don't get used with a new install.