Optical drive issues

Hi all,
I just finished installing 3 gb of memory into my 24" Imac (late 2006 model) and also 3 gb into my 20" imac (also late 2006 model). Both are 2.16 ghz and duo core intel with tiger 10.4.11.
I also received my Snow leopard family mac set today and started out to install in the 20". I insert the disk and it grinds. It will not load whatsoever.
I took a music cd and tried that, did not work. Tried like 4x and it worked. Fifth time no charm again.

Next step, hooked up both together with Ethernet cable and went through all the steps to remote install OS but it did not work either. As you can see i am not having much luck tonight.
I called Apple support, was on the phone with them for 2 hrs and they were not able to get the software installed on the 20".

I haven't tried installing it on my 24" (not ready yet). I'm sure it will work since my optical drive works and the other one does not.

I spend approx 350 this week already and it looks like I will now have to buy an optical drive (and try installing it myself) or have an authorized apple dealer do this for me.

My questions are after this long story:
Do i need to buy the same exact one or can another optical drive work?
Any recommendations?
Shall i just bring it to get done?
Any idea on cost?

Thanks again for your help.

Before even doing that, try cleaning the drive.

I have had this habit of taking a can of air and sticking it in the slot and giving a quick blast in 2-3 different directions. Used this method twice on my now 3 yr old MBP and has brought it back to life each time. (A real techie wouldn't suggest this method. Make sure you turn off and unplug the power if you do this one.)

The drive wouldn't burn a DVD here again and I finally broke down and bought a cleaning DVD last week. Stuck it in and the drive was back up again.

My 3 year old MBP is starting to give me serious issues. I have not been able to get it to recognize a DVD at all. I can't burn any DVDs, I can't install any software.. it sucks.

Which cleaning disc did you use? How much should I expect to pay in order to have it completely replaced?