There's probably little a laptop so old could do with an OS newer then Win95 anyways. With a P-133 and 80mb of ram, an OS like WinME or WinXP would kill the laptop.
I'd suggest sticking with Win95 if you're going to use that laptop.
As for security, most hackers spend their time on finding loopholes in WinXP. I doubt there's many viruses or hacks that will be targetting a Win95 laptop. I wouldn't worry too much about security on such a system (but that's me).