Oldest system you can actually daily drive?

[Cyber-Mav]

so whats the oldest system you can actually use to do your daily web browsing on? has to be able to run a modern web browser and os so no security issues.
guess its got to be something that can run win10 or win7(with extended updates).
socket 775 comes to mind, but dont know if windows 10 works on p4 or athlon xp era machines?

 

[Cyber-Mav]

biggest problem i find now is youtube videos. unless you got a new enough gpu that can do the video decoding an old cpu just gets hammered silly.