According to http://elinux.org/R-Pi_Troubleshooting# ... ic_pattern
"SDRAM not recognised. You need newer bootcode.bin/start.elf firmware"
Which, since you had a working system, can't be the case.
And when you tried the latest Raspbian you would have the latest files, anyway.
You mention September Raspbian; was that the one that was originally working? If it used to work, it should still work.
As far as I know, "testing custom kernels" can't affect the Pi itself, only the SD card, since nothing - well, almost nothing - is stored on the Pi.
Backing up your card using win32diskimager should be a read-only operation, though there could be situations where it could corrupt the file system, but re-imaging the card should cure that.
So we're down to the cards themselves, and the images you're writing to them, and the physical connection between card and Pi.
1) Try pressing the card down onto its connections while it boots.
2) The card might be worn out, so buy a new card. As luck would have it, the front page is featuring "Buy an 8GB NOOBS SD card for £5"
3) Using win32diskimager, put the backup image back, and see what happens.
4) With any of the images, try renaming any or all of the files in the boot partition, so that the Pi can't find them. It should make things worse, and so point to whichever files are causing the problem. With bootcode.bin missing or renamed, you should get no flashing. No start.elf should give you 3 flashes. Mixing & matching various versions of each from all the images you have may give you ideas, and anyway will waste a lot of time until someone else comes along to help.