18.10 hangs after install before login screen

[eduardo3rd]

I recently built a new computer with the components listed below. After installing Ubuntu 18.10 alongside Windows 10 I'm able to access the GRUB and select Ubuntu, but after the Ubuntu logo flashes across the screen I'm left with a black screen with a flashing underscore. Pressing Ctrl-Alt-F2 allows me to access a terminal session, but none of the suggestions I've found online so far have helped me get to a usable system.

System hardware:
2x ASUS ROG GeForce RTX 2080 Ti connected via EVGA GeForce RTX NV Link SLI Bridge
MD 2nd Gen Ryzen Threadripper 2950X
G.SKILL Ripjaws V Series 64GB (4 x 16GB) 288-Pin DDR4 SDRAM DDR4 3200 (PC4 25600)
ASRock Fatal1ty X399 Professional Gaming sTR4
Crucial 500GB MX500 SATA 2.5" Internal Solid State Drive

[Rubi1200]

Hi and welcome to the forum :-)

I recommend following the instructions here to boot with a liveCD/USB and then use Boot Repair to generate a summary report which you can then post here so we can see what is going on:
https://help.ubuntu.com/community/Boot-Repair

Thanks.