(SOLVED) After RAM upgrade, I get "kernel not a valid ELF file" at boot

[pstrbrc]

Running 18.2 XFCE (as a clean install) with 2x 2GB DDR2 PC2 4200 533Mhz RAM, only problem was video editing needed more RAM.
Had two empty slots, so stuck two more in. Now, when I turn the machine on, it comes up a blank screen. OK, power down, power back up, it come to grub screen. Select the only OS (Linux Mint 18.2 64bit XFCE) and sometimes it loads, and sometimes the message "kernel not valid ELF file" comes up. Power down, power up, repeat until it boots right. No rhyme or reason.
So I upgraded the kernel from 4.08.0-53 to 4.10.0-42 (this was the upgrade offered in update-manager)
Still pops the "not valid ELF file" a couple of times before I get a successful boot.
Before I start chasing rabbits, I'd like some advice. Here's my machine's info:

System: Host: bruce-OptiPlex-GX620 Kernel: 4.10.0-42-generic x86_64 (64 bit gcc: 5.4.0)
Desktop: Xfce 4.12.3 (Gtk 2.24.28) Distro: Linux Mint 18.2 Sonya
Machine: System: Dell product: OptiPlex GX620
Mobo: Dell model: 0PY423 Bios: Dell v: A07 date: 03/31/2006
CPU: Single core Intel Pentium 4 (-HT-) cache: 1024 KB
flags: (lm nx sse sse2 sse3) bmips: 5985
clock speeds: max: 2992 MHz 1: 2992 MHz 2: 2992 MHz

Do I start with a bios update? There's both an A10 and A11 available. However, they are windows .exe files, so I'm unsure how to do that with a linux install.
Altho the motherboard has 4 dimm slots, I've read that it won't recognise dimm3 or dimm4. Obviously, mine does. lshw sees them. But this didn't happen until I put sticks into these slots. Is there an explanation for this?
Do I have a grub problem, and how would I trouble-shoot this?
Any other suggestions?

[deepakdeshp]

The original and the later memory Simms should be similar types ,eg dimm3 or 4 etc.
Run the memtest in grub menu to test memory

[Joe2Shoe]

Sounds like miss-matched RAM. You can't just shove any RAM modules into a slot and expect them to work.
There are lots of variables. I always use Crucial or Corsair RAM, and they always work fine. I stay away from "off-brand" junk and I have a box of junk RAM I removed from many laptops/desktops because clients think that cheap RAM will work just fine....NOT!

[Mute Ant]

"Any other suggestions?" Prove the hardware before you look for software wobblies.

CPU and Northbridge and RAM
The Live Session memory test run to 100% pass gives you a good chance of running Linux too. It will test the CPU, Northbridge logic and the RAM you have fitted. A fail does not necessarily mean you have a bad RAM stick. It's a delicate system, having more than one stick fitted. It looks easy, but it's right at the edge where digital meets analogue. You may have seen wiggles in the circuit tracks between the processor and the RAM? They are to get the signal timing spot-on, it really is that critical. If you can spare the time, test the RAM sticks one at a time in the first slot. A fail there means the stick really is bad.

OS Storage Partition
There's an easy read-only-everything test for your OS partition. You can run this from a Live Session or from the installed system, it's not hazardous.
o Install the gddrescue package... sudo apt-get install gddrescue
o Read the whole drive, or just a partition, throwing away the copied data as it arrives... sudo ddrescue /dev/sda /dev/zero --force
If your drive is reading properly, this should finish without any errors

OS Integrity
In the running system, you can test the OS for integrity with the debsums command...
o Install the debsums package... sudo apt-get install debsums
o Test for not-OK files... debsums | grep -v OK
A few unpacked files get modified after installation, so you get a few 'FAILED' reports, but mostly the installed binaries should match the version from the repository.

[Flemur]

Keebler has released a patch!


(I'll go away now...)

[Joe2Shoe]

You can also test the memory in the Terminal:
sudo memtester 1024 5

Good luck.

[pstrbrc]

AHA! Finally figured out memtest86+. Got a bazzilion errors when I ran it with all four stick in. Pulled out #2.3.4 and tested first stick. Seemed good. Repeated three more times. All stick checked out. (Wait for it.) Put first two sticks back into slots 1 & 2. Checked out. Popped out those two sticks, and put the second two into slots 1 & 2. Checked out. (Wait for it.) Put sticks 1 & 2 into slots 3 & 4. A bazillion errors. Seems the new memsticks are good, but something is wrong with slots 3 & 4. (sigh) 4 gb just might be the limit.