Update = After completing troubleshooting, a DELL-Cares agent setup a motherboard exchange.
I bought a XPS i3 10100 a couple of weeks ago and it worked fine until the other night. I replaced the main cooling unit with the (Noctua NH-U9S, Premium CPU Cooler with NF-A9 92mm Fan) and replaced the stock exhaust fan with another 92mm Noctua fan. I also added a second 8gb ram stick to make it 16gb. I also added a ZOTAC GAMING GeForce GTX 1650 OC 4GB GDDR6 128-bit Gaming Graphics Card. Everything worked fine for a week. Then I got tired of all the Dell bloatware and started uninstalling some programs. After uninsatlling several Dell programs, nothing that looked too important, I restarted the pc. When it came back, it started running a Dell Motherboard CPU Fan Test, which it hadn't done before. It ran the fan at high speeds for about 45 seconds before a CRITCAL ERROR message popped up and said Fan Not Detected. I closed the window and it restarted by itself and booted like normal. I checked everything when it booted and everything looked fine. It ran fine for the rest of the night and I put it in sleep mode when I went o bed. The next morning it wouldn't boot up and the power button started flashing 2 amber and 1 white light in a loop. That's where it is now, I called tech support but nothing they suggested worked. Based on the error light code, it looks like it's possibly a fried motherboard? I'll probably just take it to best buy and have them look at it.
XPS 8940, i3-10100 won't boot up