Win 7 if you are lucky, most run xp. Modern ones run Android or iOS. But to your point you can basically go back to the archives of the 90s internet and go on

Win 7 if you are lucky, most run xp. Modern ones run Android or iOS. But to your point you can basically go back to the archives of the 90s internet and go on a shopping spree of vulnerabilities for dos looking at Trojan/virus code.