Hardware: 6800K on AsRock X99 Extreme4 EVGA 1050Ti SC 4GB 16GB (x4 4GB quad kit Fury) Samsung 840Pro (OS + Apps) plus 256GB Velociraptor (SATA.0 and SATA.1 respectively) Seasonic Plus Platinum 650W OS: W10 2016 Enterprise LTSB 64bit The above system has been running flawlessly since being build back in 2017 One year ago, due to work, I moved to a different country and left the PC back. Couple months later, I went back, disassembled it, carefully packaged the parts (all except the FullATX case..) and took it as hand luggage. Upon arrival, I put everything back on a new Phanteks Eclipse P300 It wouldn't start. Power was working ok, but no signal to my new HP DreamColor Z27x 4K screen After bashing my head for couple of hours, I decided to try switching to secondary (backup) BIOS (this was done by changing jumper position). The thing came up and running. Whilst I was there, I also did replace with CMOS battery with a new one But here is where the real problem starts I tried to update to a latest driver from nVidia (528.49 dch). Got an error that is was not supported and had to get a 'standard' version instead. OK. I did I went back as far as 472.47. Extracted. Update via Device Manager The screen goes flasing/changing resolution/blacking out as it always does during GPU drv installation But then it goes black for a long time (till eventually the monitor went to stand-by) Power down (as there was no response) Power up - after the initial Windows loading screen, it all goes black again From there on, I spent half day going via Advanced/Recovery, where I was removing the driver (DISM) in order to be able to load windows, where I tried tons of different versions (game ready and studio) Eventually that led to a clean install 2016 LTSB. Trying again. Same Then I thought to give 21H2 (2021 LTSC) There I was able to try the DCH instead. Failed, exactly same way. Screen goes black, several seconds after the driver is being updated and unable to boot into windows afterwards (so in all cases had to use DISM to roll back the driver) I have also tried to install using the .exe installer. Same result I have of course unplugged-plugged the graphics card as well as the RAM modules In all cases (1607 + 21H2) the GPU works ok as 'standard display adapter'. But obviously I need more than that That system has been working normally all those years and now it just won't accept the nVidia package for a driver What else can I try? (I don't have a spare GPU to try it out though..) Could it be some sort of incompatibility with the new monitor? Because the whole thing blacks out after attempting to change screen mode (resolution, refresh rate?) This is a 4K monitor. My previous (Eizo Flexscan) was 1080p. Connection is (as back then) with DP Could this be initiated due to something wrong with the motherboard? The BIOS corruption got me thinking about this, but after I swiched to the backup one, everything seemed OK (I reflashed the primary too) BIOS settings? I didn't see something that could be intrusive. Initially for some reason it was set to CSM, but then I put it back to all UEFI All other drivers, are latest ones from AsRock, for Win10 64 e.g. INF(v10.1.2.10) RapidStorage(v18.104.22.1682_PV) There are no signs of something unusual in the Device Manager And in all cases of fresh OS installations, I ve also took the hassle to update to latest cummulative update, before starting playing with the GPU drivers I don't think there's anything I haven't tried yet, so I mostly wrote this here out of despair and not expecting to find a solution. I just feel like to throw the whole thing out of the window. Is there anything I could possibly try before I get to that point?