Sounds like a defective Grub to me. You might try one of the Grub repair
utilities.

Can you suggest a good one Leslie Anne? I have a grub problem
too, it ignores one of the operating systems on the old desktop.

I've had one called just "Grub Repair Disk" which works very well for me.
Last time I tried to find it online it didn't come up but there was one
called "Super Grub Repair". Haven't used it but it sounded good.

I don't think it is a grub problem as it goes through to the login
screen and allows me to input between 3 and 5 characters of my password.

If it goes to the login screen then you can rule out grub and the boot
process. It make take a re-installation of the desktop (not distribution).
You could remove ubuntu-desktop and re-install it without affecting Ubuntu
itself (you will need to get to a command prompt to accomplish that). You
could try changing the session before you login and see if that helps. It
is likely the window manager not playing nicely with your graphics driver.
Different desktops have different window managers. I always install more
than one to help troubleshoot such issues.

Another candidate for "nomodeset."..........

I tried the "nomodset" and it didn't help.

All I can suggest is that you try other options described on this page:
https://help.ubuntu.com/community/BootOptions