PC won't POST

Man, yesterday my PC booted up without a single beep. I started thinking, maybe the internal speaker just died? So, I rebooted the thing. Same exact issue. It wouldn't even let me touch the BIOS, didn't show any boot info at all—just went straight into Windows.
Today? Now the PC won't even POST. All the fans are spinning, including the PSU. Nothing.

I tried pulling out the RAM and the GPU, but still no beep. Then I yanked the HDD and the SSD... still dead silent. Did the motherboard finally kick the bucket?

Specs:
Intel Core i5 Dell Inspiron
Asus M5a97 R2.0
2x4GB HyperX 1866MHz
Nvidia GTX 970
SSD+HDD
EVGA SuperNOVA

Any kind souls out there have some advice?

It's hard to give you a solid answer without more info. You haven't mentioned if the rig was running fine until now, if you've swapped any hardware lately, if you actually cleaned the thing out, or even which drive your OS is sitting on...

Was the SSD + HDD combo working okay for you?

That’s a solid new motherboard, so don't go jumping straight to replacing it. Is your keyboard plugged into a PS/2 port or USB? Sometimes USB keyboards act up when you're trying to hit the BIOS. If everything seems fine there, it might be a GPU issue. Try reseating the graphics card and double-check that every single connector is clicked all the way in...

If that doesn't do the trick, try resetting the BIOS...

Everything has been running smooth as silk until now. My motherboard is only six months old and has been performing flawlessly. I’ve had my SSD and HDD combo for about a year and a half—zero issues there. Then, about a month and a half ago, I decided to upgrade the power supply and grab some new RAM. I’ve already played around with the memory; tried one module at a time, then the other, then even swapped the sticks from slots 1 and 3 over to 2 and 4 (moving them from the blue slots to the black ones).
I pulled the GPU out and reseated it, but nothing. The fans on the card spin fine, but there’s no POST, no beep codes, and certainly no Windows. So, I pull the GPU out entirely to see if that helps? Still nothing. No beeps whatsoever. I just let the machine sit there running for maybe five or six minutes; all the fans are doing their jobs perfectly—CPU cooler, case fans, even the power supply fans are spinning.
I even pulled the CMOS battery out for fifteen minutes and popped it back in, but it’s the exact same story. Nothing changed.

I don't really need to blow the dust out of the PC because I maintain positive pressure inside the case, but I still make sure to clean the filters every week or two. Inside, the whole thing looks practically brand new.

I’ve got a gut feeling your motherboard might have finally kicked the bucket—honestly, when you're dealing with a headache like this, there's a 99% chance the issue lies right there with the board itself.

I mean, I figured as much. I was just HOLDING OUT hope that it might be something else entirely, but honestly? That's a dead end because I’ve practically exhausted every single possibility.
But look, there are plenty of smart people on this forum, so why shouldn't I ask? Maybe someone here actually knows what they're doing and can help me out.

There isn't much I can do to help from my end—at least, not from where I'm sitting. The only thing I’d suggest is finding or borrowing a motherboard with the exact same socket you're currently using. If you test your components on that, I'm pretty sure you'll be able to get this PC up and running properly.

So, I picked up this motherboard and it’s already giving me grief. The BIOS beeps are telling me there's a RAM issue. Is it actually possible that it's just the memory? How on earth did my previous board recognize it without any problems?

I went ahead and reset the CMOS on that new motherboard, and wouldn't you know it? Now the RAM actually works. Nothing changed, really. Thanks for all the advice, everyone, I guess. The board is heading back to service... damn.