RAM errors now iMac won't boot

My 24" iMac had some graphical glitches and froze up, so I ran MemTest86 on it and got a number of errors reported on my RAM.
I had upgraded from 2x1gb to 2x2gb and kept the old RAM, so I gave that a try. This time MemTest86 itself came up with graphical glitches and reported problems on this RAM as well.
I gave up for the night and the following morning when trying to boot, all I get is the monitor powering up and the Mac boot sound. The system then reboots immediately and does the same thing over and over. Screen powers on (stays black though) and sound plays. I never get to a gray screen at all nor does the Apple logo ever appear.
Trying to boot to safe mode, off cd, single user mode are all unsuccessful, I never get out of the boot sound loop.
NVRAM/PRAM reset attempted, likely unsuccessful.
I've tried booting with 1 DIMM and 2 DIMM across the different RAM I have, but the same thing always occurs. Only time I get different behaviour is when booting with no RAM, and then I just get a beeping tone.
Any ideas on how to recover?

Try removing and reseating, if it still fails then replace the RAM. RAM can and sometimes does fail. If you still have the original RAM lying around then try booting from that to see if the errors disappear if they do then you know the added RAM has failed and needs replacement.

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