After confirming that the machine would boot on the as-shipped 40GB hard drive, I took the drive out and cloned it into one of the 250GB hard drives I have here. I then put the 40GB drive in the fire safe, to use as an "if all else fails, start over" backup, and did all of my system configuration on the 250GB drive. I swapped around memory chips between the various computers so that the Latitude -- which will become my new "flagship" machine -- has 2GB memory, while the other machines get 1 GB and 0.75 GB each, which should be okay as I don't expect to use them very often.
Getting all of my software reinstalled is tiresome, but the need to get it running isn't urgent since I can still get work done on other machines, so I'm installing stuff as I find time and can leave the machine to think about it, such as when I set it to copying many GB of documents from backup drives last night when I went to bed.
This new machine is by no means a top-of-the-line machine, but it cost less than $200 and will do everything I need to do, so I'm feeling pretty good about it.