hey guys ,

few years ago i bought a rendering desktop , was working great , lately it started not booting , restarting , sometimes bios wont post, until recently it started giving me something like "chassis was open , enter administrator password" , after the POST. never had a password , never opened anything. i cant access the bios. i tried:

-using the jumper to reset/recover, not working at all , at recovery no screen signal+nothing happens(kept it for like 30 min) and i cant access maintenance mode (same error when the jumper in normal position).
-changing ram/different slots
-changing psu
-changing graphic card
-tried to flash bios using flash memory.(cant access maintenance/recovery using the jumper so couldnt flash)
-chassis intrusion jumper added/removed
-looking online a lot. the only similar problem i found was a newly purchased same board , the guy got a refund .(no solution)
-disconnecting/reconnecting/removing unnecessary components....

the only thing didn't try yet is removing the cpu (waiting for thermal-paste)

the setup was heavily used with renders.

specs:
-board intel dx79si
-32gb ram kingston 1333 (8x4)
-gtx550ti
-cpu intel socket 2011 i7 ( cant remember the exact model)
-ssd/hdd

thanks
From the symptoms you mentioned it is most likely to be a dead motherboard, it is hard to find a similar used one in good condition these days, found a new one at pcandparts but a bit expensive
Gigabyte GA-X79-UP4 (rev. 1.1)(DDR3) (LGA2011) Link $299.00

Macrotronics also has some boards at 350# and 500$, yep, crazy prices
anayman_k7 wroteFrom the symptoms you mentioned it is most likely to be a dead motherboard, it is hard to find a similar used one in good condition these days, found a new one at pcandparts but a bit expensive
Gigabyte GA-X79-UP4 (rev. 1.1)(DDR3) (LGA2011) Link $299.00

Macrotronics also has some boards at 350# and 500$, yep, crazy prices
yeah im trying to avoid such solution :P.

the cpu was heavily loaded almost all of the time, im thinking maybe the problem in the cpu (it pasts POST check.) since it was overheating a lot , and the problem exaggerated progressively.
The probability of damaging the CPU before the motherboard (VRM, Power socket) is very very low, reaching CPU dangerous temperatures will shut down the PC immediately.
Try swapping the bios battery, see if that works.