Nec versa 4050h what operating system can i use?

i have a nec versa 4050 with a very low amount of ram 16 mb it has win 95 and sopmething that says 4.00.950b im guessing that means 4 gigs hd. i would like to run something like linux or unic on it to make it faster and also get it online theres no modem in the side no usb and only a floppy drive leaving out anything i know how to do. My questioon is what can i use for an operating system and a link to download one would be cool as im a noob and how do i get it online i have high speed internet and cant buy a modem as there crazy high and it also would not work. as i only have ethernet lines and wirless but no usb. thanks for any of your time