Maybe your IBM clone desktop or laptop PC can't do Windows anymore (certainly not XP or Vista)… but Puppy Linux should be capable of teaching an old PC new tricks:
Yes, your Projectionist endorses this distro. His IBM (now Lenovo) ThinkPad 600E now runs like a new machine, and looks as slick as anything on the market right now.
And it's a free download.
Now if only he could get his laptop's CMOS battery replaced…
[UPDATE 2008.05.16: The URL for Puppy Linux has changed — use the one at the top of this post.]