I don't think it would help. I mean, it happened before, with Win9x and then Win2000. At least this time around we got a nice notice in advance. Anyway, I'm gonna try my luck with Steams' offline mode on my big XP x64 machine (Hexcore, 48G RAM, Titan Black, large RAID-6). In the meantime, I built myself a neat mini-ITX gaming box with (ew) Win10. It's ok, if it's just a game launcher, so I don't have to do any actual work with it...

Unfortunately, I can't just drop Steam. :( Too many Games I like are exclusive to the Platform... A classic vendor lock-in...

I was thinking of ways to trick Steam into sorta being "frozen in time" with an offline XP setup, but I figured fuck it, I'm probably just gonna dump Steam. It's unfortunate that I won't have Team Fortress 2 anymore, but oh well.

What catches my attention is that you mentioned that this has happened with Windows 9x and 2000. I suspected that might've been the case, and wondered how guilty I myself would be for ignorantly using Steam all this time, not knowing of such atrocities. I am utterly through with this. If I recall correctly, I started using Steam for TF2, and everything else sorta just ended up tagging along. I will be leaving, feeling as if I've sacrificed next to nothing other than Team Fortress 2, despite my sizeable collection of games, and despite my absolute lack of income. I expected that something like this would happen to screw me. For those who didn't, I hope this can serve as a wake-up nudge to treat Steam with vigilance.

@GrandAdmiralThrawn, is not necessary to delete Steam client and to not play in games which you have bought. Just don't spend a money to generate a profit for Valve.

There are other people who thinks as you. Add me as friend for more details.