I had Windows 10 installed on C:\ working well. I wanted to dual boot Linux so I installed via USB stick targeting a 2nd SSD installed for that purpose. When it came to where to place the boot code I selected the 2nd SSD "sdb." I didn't think to boot off that drive from the BIOS, expecting Grub to just work. I reinstalled using sda to place the boot but then ubuntu still would not boot. Ubuntu just displayed a screen but wouldn't even respond to Ctrl-Alt-Delete. I found Windows displayed on the Grub boot menu and it could boot but above it at the top of the list was ubuntu which did nothing beyond what I described above. I must have deleted the partitions and reinstalled ubuntu on sdb7 times each time trying to name a different partition on sdb.
Perhaps I'll try again when I get up. I've been up all night trying.
EDIT: Okay...I have some really pertinent information. I noticed an error message but, duhh, I ignored it thinking it insignificant. It is displayed when I try to install ubuntu into my target machine. However, I tried my older computer where the errors did not appear and the install was successful. I photographed these messages and here is the text:
[ 0.018063] ACPI Error: [\SB_.PCI0.XHC_.RHUB.HS11] Namespace lookup failure. AE_NOT_FOUND (20160930/dwsload-210)
[ 0.018063] ACPI Exception: AE_NOT_FOUND, During name lookup/catalog (20160930/psobject_227)
[ 0.018097] ACPI Exception: AE_NOT_FOUND, (SSDT:xh_rup08) while loading table (20160930/tbxfload-228)
[ 0.024062] ACPI Error: 1 table load failures, 4 successful (20160930/tbxfload-246)
See this post about above: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1584407
Whatever this means it would appear to provide a reasonable explanation.