Very weird it can’t play videos at all.
I'm sure it can. My guess: either VLC is broken and a different or lighter player would work, or OP is picking the wrong videos (for a really slow CPU, you want older/less compressed codecs—I bet it would do MPEG1 just fine, and might even have acceleration for it).
These days, I only manage to rewatch about one series a year unless I'm convalescing from something, but here are a few series that have made it to the head of the rewatch queue over the years: