Maybe you never had USB power problems before, but if the USB power circuitry failed you'd have problems now. And that could explain why the keyboard LEDs don't light up. Plug that bootable USB stick into PC with power off. Then power on and tap F12 to see if you can open that  menu. If it opens look for option to boot from USB and see what happens. But again, that sounds like maybe the USB power supply has failed Maybe you can borrow a USB hub with its own power adapter from somebody?  Time to toss in the towel and buy a replacement motherboard or just replace the entire PC?  Or consider Dell Out Of Warranty Repair.  Your PC, your budget, your decision.
Weird behaviour citation = The fans would come on, the power light on the front was white and the lights on the back was green (normal behaviour), but there was no display. The hard drive light would also turn on, but then turn off until rebooted. No mouse or keyboard inputs worked, either. Specs: Dell Inspiron 660s Intel Pentium G630 4GB RAM 500GB HDD Windows 10 and Linux Mint (upgraded from Windows 7) Feel free to either read the whole question or the last section. Ok, so here's some background that isn't as related to my question, but may contribute to it:   Around two years ago, my PC froze and glitched like this: [IMAGE] My PC would then give me a RAM error (2 beeps), and would take ~20-30 restarts (still with 2 beeps) before it started working again, and I would get this error: "Alert! Previous attempts to boot failed at checkpoint [0019]." Now it would take two boots to turn on, in which in the failed boots it would (weird behaviour citation here). At some point, I did a Dell diagnostics test from the BIOS with no issues, but then 1-2 weeks later, the PC would glitch out. This reiterated for a few months. Reseating the single stick of RAM into a different slot seemed to work, and it hasn't glitched out since. I don't know for sure, but I suspect a bad slot.   Here is some more recent background:   All of a sudden, around half a year later, the PC refused to boot. The number of boots it took to successfully boot before it changed is as follows: 2, 3, 5, ~10, ~30 , 63. After those boots, the PC refused to boot, taking 60+ boots with Jo success. (weird behaviour citation here) I tried: Reseating RAM and CMOS Switching the RAM between the two slots Using a different monitor and power cable Switching between HDMI and VGA Removing the dust in the system Replugging the hard drive and optical drive data and power cables Removing the hard drive and/or optical drive   Interestingly, I could get a different outcome if I unplugged the RAM (2 beeps) or unplugged the CMOS (PC wouldn't turn on at all).   Here's where my current problem comes in:   Around half a year later of no boot attempts, the PC finally booted up, with the same "Alert! Previous attempts to boot failed at checkpoint [0019]" showing up, but the PC worked fine. A memory test with a Linux program called memtestx86 showed no errors, and I used the time to move my most important files from it. The boots it took are as follows (successful boots also showed the same Alert! message) 2, 3, 7, 1, 3, 5, 4, ~76 and counting   This time, instead of beeping when it didn't boot, (weird behaviour citation here) would happen. I tried the same things as the list I wrote before this, with no avail. I replaced the CMOS battery after boot 64, seeing that this could be a result of that, and at boot 70 and 74, I got five beeps: a CMOS battery failure. Placing the original CMOS didn't worked, either, and this is where I'm at. I'm guessing it's a problem with one or more: Power supply, CMOS batteries, CMOS circuit, and/or the motherboard.
Still getting CMOS battery failures after replacing CMOS battery