Laptop won't boot up when keyboard is plugged in

So, I’ve been dealing with this Dell Inspiron, and honestly, the built-in keyboard has been a total lost cause for a while now, though the machine itself seemed fine since I just used an external USB keyboard. But then, out of nowhere, everything went sideways—now the laptop won't even boot up if that faulty internal keyboard is still plugged in. If I disconnect it from the motherboard, the thing actually powers up just fine, lights come on, charging indicator works, the whole nine yards...
Is it actually plausible that a busted keyboard could prevent a laptop from even starting up, or am I looking at a motherboard failure here? It feels pretty pointless to go out and hunt down a replacement keyboard on eBay for $67 if I can't even get the damn machine to turn on, especially since it seems to behave itself once I bypass the broken one.

It’s entirely possible that it’s causing a system freeze, because I've actually had this happen before where a faulty USB keyboard would lock up my entire desktop PC, and then the exact same thing would happen when I switched over to my laptop.

So, I’m dealing with this whole mess involving a laptop keyboard. It’s a bit of a weird one, I guess. Basically, whenever I pull the battery out and then pop it back in, the machine just refuses to boot up if the keyboard is still plugged in. I tried disconnecting the ribbon cable from the motherboard entirely—just to see what would happen—and yeah, the laptop starts up just fine without it. The thing is, the current keyboard has been acting up for ages now, so I'm looking at picking up a replacement on eBay or maybe Craigslist, but I can't quite tell if the issue is actually with the faulty keyboard itself or if there's some deeper problem on the motherboard that's causing the interference...

Maybe just take it in for a quick checkup, since they usually do inspections for free.
If it's the motherboard, don't go dropping cash on a whole new laptop. But if it's just the keyboard? Buy a new one... I guess.

I had something similar happen with my PC once. My keyboard died and suddenly the whole thing wouldn't even boot up.

I’d say there’s a 99.99% chance you’re just looking at a faulty keyboard, because if something on the motherboard had actually fried, the whole laptop wouldn't even be booting up, or you'd be dealing with some massive, system-wide headaches while trying to get anything done.

What kind of service is actually going to be free? The warranty’s already dead and gone. It’s actually my buddy's laptop, so I guess I'll just tell him the keyboard is fine and call it a day... if everything else seems to be working okay, I mean, there's really no point in me messing around trying to reconnect a flat cable to the motherboard when it's functional enough, right? I'll just let it sit there like that, or maybe he can just use an external keyboard until he finally gets around to buying a new one.

What kind of service are you even talking about? Just order a new keyboard on eBay and swap it out yourself; it’s a quick fix and honestly way cheaper too.