I used to played something like spelen.nl on school but I wasn't really playing that much till I found out about Tankionline here is where my game adiction started
All of this on my first PC with specs:
CPU: i486DX / 50 MHz (i think, it was some sort of 486)
RAM: 8 MB
GPU: Some sort of Voodoo card
HDD: 40 MB
OS: Win95 and DOS, need to boot into DOS to play games duo to memory limits!
Timesplitters still the best FPS game to this day, it was even made by some of the members who made Goldeneye and also uses Goldeneye's game engine too.
First game I ever played on PC was team fortress(2008) then i started watching SFM's and shit like that.. I saw someone that made a tutorial like how to make a SFM and he did it in gmod.. so gmod is my second game i ever played on steam(2008), then Minecraft on 2011 loool(also ray-man PS2, tekken ps2, gta vice city and gta san andreas on PS2) (also css, 1.6, hl2e2 and portal 2 xdddd forgot to metion them)
Reason for playing on PC when I was that young was because I went to Israel with my family when I was 6 years old and I had no friends in school because I didn't speak Hebrew(the main language in Israel), so I had to play PC or sum like that.