Question I've connected the front panel connectors right and still my pc won't turn on

[CharlieTelling]

I just recently built my pc with a Asus Rog strix b450 f gaming ive connecting everything double checked motherboard RGB turns on but when I press the power button, nothing. Can someone please help me

 

[jeremyj_83]

Is the power switch on your PSU turned on?

 

[rgd1101]

full system spec? include make and model of the psu

 

[CharlieTelling]

Is the power switch on your PSU turned on?

Yes my whole spec is
Asus b450 f gaming
4x8gb hyper x furry 2800 ram
Power supply brand unknown it's from my old pc but it's 750w 80+
Rtx 2060 super gigabyte
Ryzen 7 2700
Case Corsair carbide 275r

 

[rgd1101]

open the case and get the make and model of the psu

 

[CharlieTelling]

Yes my whole spec is
Asus b450 f gaming
4x8gb hyper x furry 2800 ram
Power supply brand unknown it's from my old pc but it's 750w 80+
Rtx 2060 super gigabyte
Ryzen 7 2700
Case Corsair carbide 275r

open the case and get the make and model of the psu

There's no writing on it

 

[Mtop]

How do you know the wattage without any labels?
With the power supply plugged in and turned on----- Which RGB light is on? what other lights are on on MB?
Do fans spin?

 

[rgd1101]

old generic psu? got another good psu?