I have a brand new computer build in an old case where everything seems to work except for the front panel connections (the front panel buttons still work).
Honestly, I'm not sure if this is the right category, but I have a couple of issues.

One, when I push the power button on my desktop case, the computer seems to turn on normally, all the lights and fans turn on and there are no beeps. When I push the power button again, the computer stays on. I've tried holding it down for 5, 8, and 10 seconds but it still won't turn off. I can only turn it off by flipping the switch on the power supply in the back.

Two, even though my monitor plug-in is a DVI and my motherboard has a corresponding DVI port, I still get "no signal" when I start up the computer with the cable connected. I've tried connecting the cable to three different graphics cards instead and nothing changed. I also connected the monitor to another desktop and the display worked, so I've ruled out the monitor and DVI cable.

Specs:
Motherboard: TUF Gaming B450-PRO https://www.amazon.com/gp/product/B07R4N68SR/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
CPU: AMD Ryzen 5 2600 https://www.amazon.com/gp/product/B07B41WS48/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
Case: Cooler Master HAF x nvidia https://www.newegg.com/green-cooler-master-haf-x-nvidia-edition-atx-full-tower/p/N82E16811119236
Graphics cards: EVGA GeForce GTX 670, 570, 460