iMac mysterious failure! (maybe RAM?)

Oct 4, 2011
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My iMac was working just fine a few days ago. When I got this computer it came with 1GB of ram and I very recently upgraded it to 2GB. I installed my programs on it (which need 2GB to be useful) and I then ran a software update. The software update was in progress for HOURS and wasn't making any progress at all. So I held the power button and shut it off. Next time I turned it on I didn't have the power chord all the way in, and the computer sounded like it had the fan running extremely high. So I thought silly of me, and restarted it again with the power chord fully in. It was all working just fine. I watched a few shows on the internet, and left the computer on until the next day. I come back and go to hit back in the browser and I got nothing but a spinning mouse wheel. About an hour and a half later with no progress, I shut it off. NOW THE COMPUTER DOESN'T SEE THE STARTUP DISK! It makes two beeps (one short and the next long). I tried to run DiskWarrior to rebuild the directory, but it does not see my computer's HD. I researched the two beeps and found they may mean incompatible ram.
So I had a way of checking the ram myself, I swapped it with 2GB of ram from my mac mini. My mac mini sees the iMac's ram, and the iMac has the mac mini's ram and still the same problem. I can't believe this. Haha sorry about the details but I thought I should explain anything that might have led up the problem. Does anybody know what's wrong?

I have four RAM chips that fit into this computer, none of which in any combination help get the computer started. Every RAM chip works in my mac mini. This is my Mac Mini... Mac mini "Core Duo" 1.66 Specs (Early/Late 2006, MA206LL/A*, Macmini1,1, A1176, 2108) @

And this is the iMac...
iMac "Core 2 Duo" 2.0 20-Inch (Al) Specs (Mid-2007, MA876LL, iMac7,1, A1224, 2133) @

The RAM that the iMac had was one of the 1GB original chips that comes with it.
I added 1GB PC5300 DDR2 667MHz 200 Pin SO-DIMM

The RAM that the Mac Mini came with was two 512MB 2Rx16 PC2-5300S-555-12-A3 chips
Nov 28, 2007
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Blue Mountains NSW Australia
Your Mac's Specs
Silver M1 iMac 512/16/8/8 macOS 11.6
You do have the original system install discs? Good boot from Apple Hardware Test and it will check memory during the extended test mode. And was the memory purchased from a Mac dealer as using incompatible memory suitable to Windows machines does exactly what you are describing?

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