You're very welcome.
Unfortunately, " irishman_team_kilber" is terribly wrong and has no validation (at least not in the current state of PC picking) in this discussion, not to bash him, though.
Upgrading an existing desktop (which the Original Poster already stated that he/she doesn't even have one anymore) is often times impossible because the mainboard won't support certain upgrades.
Also, "one off the shelf" isn't a bad thing anymore, Pre-Built Desktop PCs have become aware that they aren't going to sell unless they deliver. i don't know if looking at certain online retailers, or physical, local or chain stores are putting sub-par hardware in their machines and selling at a premium cost... but the links i provided are very solid.
However the OP doesn't have PC building knowledge, and i wouldn't recommend buying parts for a PC if you haven''t been installing parts before.
Once again, I would go with the Ryzen Cybertron Pre-Built Mid-Tower PC Because it has a great CPU, great Graphics card (GPU), expansion for larger SSDs, and compatibility for 64GB RAM. That right there is a seriously Beast PC for Under $1,700... i built my PC from individual parts and it cost me around $2,400 to manage the system specs.
I did choose to go with a preference in colors and RGB lighting, airflow, Future-Proofing and expandability... in the long run i am happy with it. to elaborate, i not only run 3ds max, unreal engine 4, photoshop, mudbox, and crazy bump... i am a music producer using FL Studio and a Novation Launchkey 49 MK III, a Mixman DM2 32-track mixer, and playing on unlimited Synthesizer generators routed to my MIDI keyboard with FX, EQ, and real-time mixing, it's demanding of my resources.To make things more demanding, i have a Creative Fatal1ty Champion Recon 3D pci-e Sound-card with THX TruStudio DSP, surround spatializer, crystalizer, and a duplex-capable recording function which takes up a lot of cpu when playing from FL Studio into Adobe Audition with THX's DSP enabled to master my tracks.
Also, i am Irish as well, and i have the Corsair Graphite 230T series Case in Rebel Orange, with green and white LED 120mm Fans in the top and front slots... and ASUS Aura set to dynamically fade from green to (gold[yellow], not white) to orange, and it is a great looking machine, the RAM also fades accordingly,