Question PC won't boot, but everything's plugged in

[beatsinmyhead99]

Yesterday, I built a PC and it worked perfectly fine. Today, it doesn't turn on. I tried reseating the ram, cmos and gpu, and unplugging and replugging the front panel connectors, cpu cable and 24-pin PSU connector.
Specs:
Asrock B660M Pro Rs motherboard
Intel i3 12100F
AMD RX 6600 8GB
24GB DDR4 RAM
Thermaltake 600w 12v 80 Plus PSU

 

[Darkbreeze]

What do you mean by "doesn't turn on", SPECIFICALLY? Do you mean nothing at ALL happens when you press the power button? Or do you mean there is clearly power to some things like the fans, lights, etc. but nothing comes on screen. Or do you get a "no signal" message on the screen along with some indication that there is power with fans etc.? Or do you mean everything seems to work fine but it won't POST. Or do you mean it will POST and you can get into the BIOS but it simply won't boot into Windows?

What is the ACTUAL model of your "Thermaltake 600w" power supply and how long has it been in service?