Try it without the Quadro 4000.  What do you get?

You said you "think" you got diagnostic code 2,3,4.  Is this consistent when you try turning it on?

If the size 2032 CMOS battery is 5+ years old, it's time for replacement.  Sometimes a bad battery will also throw a bad error code.

my bad i forgot to say i did that and pc works fine, i only got error before i removed it

Might be time for a different GPU card if you can try one.  They do go bad on occasion.

no my pc is working fine on integrated gpu

yea i ordered another q4000, ill follow up if its still not working

Ok well I'm still having issues, I tried it with the new q4000 and I get a solid blue light with diagnostic lights 1234 lit up, I take out the gpu and it still works fine

How do you clear jumper? I haven't put new battery in and I'm getting blue light with 1234 and nothing on display

Do you mean same diagnostic light 234 when new gpu is in?  This 234 code is supposed to suggest possible usb failure, but that does not help.  Since the old card used to work but now both new/old card stop working w 790, logical suspicion is somehow bios cannot pass firmware test/POST when this card is in, but is okay to POST when this card is out.  Have you already replaced cmos battery and cleared cmos settings by jumper reset?

thank Brad for already helping you on how to clear cmos.  just to illustrate on the 790 MT motherboard the cmos and password jumper pins are shown in red circle (there may be a silkscreen of RTCRST next to cmos pins).  default blue jumper is on password pins.  after ground your fingers on chassis, you move blue jumper to cmos pins for 5-10 sec then move back to password pins.