ThisFieldIsRequired

I guess you gotta go back to "the beginning", if you wanna do that...

"Pre-built PCs & OEM PCs". When their prices get down to this price range / value for money, to me, they're OK. And before anyone starts the "yeah, but finding a GPU that works with a 199£ HP Z400 with16Gb of ram & 4c/8t Xeon W3550 / etc. ain't that easy...". It's no SFF one with those stupid PCI-E x4 / 25W (instead of 75 W) motherboards. (12 month warranty?. Bloody hell, here they usually gives those 3 to 6 month warranty. And prices that are 1.5x - 2x higher)

"boot beep - freezes - It makes a beep after some sec and does it again forever like a loop." A: How about telling us what motherboard you've got?. B: POST & beeps codes (1 Short Beep + Repeating short beep?: Post + No power, loose card or short = Try again without your GPU.)

Your PC - not mine - so turn it off if you want. (I personally wouldn't stop my Sunbelt Personal Firewall, even for a microsecond.) I would've gone to War Thunder's forums with this, 'cause the likelihood of people knowing the answer "might be" a little bit higher there than here...

Put your GPU into the 2nd full lenght PCI-E (x8) slot and try again?. = If it starts working after that ==> The 1st PCI-E (x16) slot might be dead.

I've a feeling that Intel have learnt their lesson... ...unfortunately.

Yes: Don't throw more money at it.