I installed Lubuntu 18.04, the LXDE variant of Ubuntu, on an old Dell Inspiron 1525 laptop. It worked, but every bootup would take several long minutes.
Turns out that this is a known problem for this Dell laptop reported here. I followed these steps:
$ sudo vi /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=SVIDEO-1:d"
$ sudo update-grub $ sudo reboot
Boot time dropped dramatically to about a minute after this change.