If memory serves me right the PPXs were the forerunners to the Latitudes, or are from that general family. They were a business laptop. I think I actually had a company one at one point circa 2000.
If it's running XP (I'm guess SP1 and barely?) it might just barely meet min operating requirements for Lubuntu IF it's had its memory upgraded and the XP is removed. Sporting a Win95 sticker, probably something like a P2? Maybe a P3. There may be 512MB, but I don't think there'd be more then that. It MIGHT, under the best of circumstances, meet min operating requirements for some modern desktop linux distros, but just barely. The answer is probably not at all.
OP, you're probably looking at something like Puppy or DSL. I wouldn't risk trying to resize the partitions on such an old harddrive. If it's original to the machine it's a miracle it's running at all. Even if it's half that machine's age it's still living on borrowed time.