IMHO, if you want a great chair then go with one of the better Office chairs made by Steelcase, Hon, Herman Miller, and a few others.
I did and I'll never look back.
That should go together pretty easy. Zip ties & Velcro let you mount fans & SSDs wherever you want without messing with screws. Aim the airflow where your want, like at an NVME drive, not just where you case design forces you.
Don't forget the CPU thermal compound.
I use 80GB RAM at the moment and am giving about 30GB to Primocache in order to cache I/O to all SSDs and HDDs. I have also given Primocache an old 128GB SSD in case the RAM cache fills on some monster transfer to HDD.
The RAM is fine. Go with the best price.
The PSU is also fine.
The GPU choices are pathetic. For a few dollars more you can get a used GTX 1070 and at least have a card that will survive your next CPU/MOBO upgrade.
I would not buy any of the items you want new. Your rig is old but still quite capable. Nonetheless it is not worth much money and upgrading it will not make it worth much more so buy used stuff unless you can find very cheap new stuff.
The #1 upgrade (like everyone in here recs) and which you...
I think you will be wasting a lot of money.
If you must go Intel, then the paltry 16 PCIe lanes in the i9 you picked is critical. Your money would be better spent on one of Intel's LGA2011 or LGA2066 platforms with 40 lanes.
OTOH if i had plans to spend that kind of dough on a new PC, I'd go...
You might want to just upgrade your Windows to Version 18362 first. (1903)
Its new mouse configuration is light years ahead of the old one.
Regarding the errors,
Open a command window (run as administrator) .
At the prompt enter "sfc /scannow" without the quotes.
This will take a few minutes...
I've had 2 picky ASUS boards did that to me several times after HW changes.
Your board probably has a dual bios option like the high-end ones I've had. Unplug everything from the board except the KB/Mouse/Monitor.
Try Switching to the backup BIOS. Mine had a button on the IO panel . and I think...