We've had an old Dell Latitude E6400 laptop sitting under our downstairs computer desk for three or four years now and on a whim I decided to see if would even boot up. It got part way, but as I recalled it had been dropped by the kids a few times and there was probably hard drive damage. I have a few old 2.5" mechanical SATA drives lying around so I decided to swap one in and see if I could install Windows 10. The fact that the laptop seems to be pre UEFI ended up preventing me from booting up off my Windows 10 installer flash drive installer. So at that point I decided to just install a copy of Ubuntu MATE in order to get it into a workable state while I wiped it down and cleaned up the kid-grime on the exterior. That install went smoothly and really didn't take all that long despite installing on a mechanical hard drive rather than SSD.
Once I had the Latitude up and running again I decided to see if I could find a couple appropriate so-dimms that would allow me to upgrade it to more that 2GB RAM. As luck would have it I was able to track down a pair of 2GB RAM chips in my stash of old parts without too much of an issue and those worked fine. The one caveat I had forgotten was that for a certain class of Core 2 Duo laptops from this generation1 their motherboards are only actually capable of addressing 3 out of the 4GB total. So while it's an improvement to do the upgrade it's not quite a big as I had hoped.
I also did some further Windows 10 installation research after the fact and it sounds like it is possible to install that upgrade, but the successful people performed the installation on top of an existing Windows 7 installation. That method helped ameliorate the driver support difference as Windows 10 will try to continue using any existing Windows 7 drivers that don't have a Windows 10 replacement. I may still pursue this angle as this Latitude will mostly be seeing use as a spare laptop and potentially a game machine for the younger kids and there are far more gaming options on the Windows side of things. It would also probably be worth it to pick up a cheap 128GB SSD now that I know the hardware is running fine overall and before anyone starts using it again too regularly, but we'll see how it goes.
Also true of some MacBooks from the same era.