[Help] New (used) 10700 not working?

[Valent117]

Hello there
Here is the deal
Just got a decently priced i7 10700 (110€) to replace my i5 10400f
Motherboard is B460m aorus pro, updated to latest bios F8, nvme ssd and 4 sticks of 2666 ram, windows 10 updated, 600w psu but it run my 3080 no problem
Got the cpu today, installed it (cooler, mx4 and isopro alcohol cleaning for cooler and cpu) and nothing, fans spinning no display
Disassembled, put the 10400f back, working as before

List of things i tried/did :
-uninstalled the i5 from device manager (first step when i came home)
-always switch off psu (at some point i stopped unplugging it im sorry)
-onboard leds, normal behavior with i5 (cpu then dram then vga then boot then off), CPU LED stays on with i7
-clear cmos, upon putting back the i5 i got confirmation it worked (didn't fix problem obv)
-switching video output, all ok on i5 but nothing on i7 (tried hdmi and dp from gpu, then hdmi and dp from motherboard just in case it didn't output on gpu)
-io port/initial display output/ internal graphics not available (anymore?) in bios when i5 in installed (bc no igpu)
-removed gpu to be sure it would output on motherboard (cpu led stay on and fan spin and nothing more)
-unplug replug cpu power (semi modular psu so on the cpu side it can't be checked
-there is no dirt on the bottom of the i7
-i7 has some marks but my (brand new when bought) i5 has basically the same
-swapped back and forth no better
-i don't have any other ddr4 ram (thought of trying some 2133 or 2933 idk) but my 2666 are working fine with i5
-spamming bios key with i7 installed, didn't work (works on i5)
-removed the sata m2 ssd
-my peripherals don't light up with i7

edit
-remove 3/4 ram stick no better
-set ram to 2133 in bios no better

I can dispute the sale, but I rather fix the thing you know
This is not my first pc i built or upgraded, im literally writting this from my laptop with most internal swapped

Open for suggestions about to go to sleep (mah gaming night ) but will reply to the first comments

Thanks for help

 

[JWNoctis]

Pictures of the processor would be nice, but probably not too helpful at this point.

There's a recent article elsewhere about an overclocker who ordered a used processor online, and got shipped a cursorily indistinguishable, pristine-looking, and studio prop-quality boilerplate, with nothing inside.

More likely it's just a dead chip. Good luck with the return.

 

[Assimilator]

You've covered all the bases, unless you can get hold of another board to test the CPU with I think you got a dud. Could be honest mistake, could be shipping damage, could be a scam, but really all you should do now is send it back.

 

[Valent117]

You've covered all the bases, unless you can get hold of another board to test the CPU with I think you got a dud. Could be honest mistake, could be shipping damage, could be a scam, but really all you should do now is send it back.

No other board, just contacted the seller
It was nicely packaged and seems undamaged