윈도우 7 스팀 설치 - windou 7 seutim seolchi

That's very odd. I haven't used Windows for a long time, however upon checking a Steam Forums people generally concur that Windows 7 will not be supported for long;

https://steamcommunity.com/discussions/forum/0/3570700856113376870/

https://steamcommunity.com/discussions/forum/0/1747894017709951068/

So it doesn't look great..

With that said, if you have free reign of the HDD (that is, you can install/wipe/do what you like with it) might I suggest Linux?

While I understand that might be quite a dubious proposition this is exactly how I got into Linux - a laptop refused to repair or boot Windows and I was told it would be best to just throw it away. I instead installed Linux on it and got another 2 years out of the laptop before I accidentally broke it.

I'm not sure what games you're hoping to run but aside from a few Call of Duty games most of my library (500+ games) works fine with Linux+Steams Proton.

Obviously getting it working on Windows 7 would be ideal for you, however if other people agree that Windows 7 is somewhat outdated (and that would be a shame because I got on okay with that OS) then you're not entirely out of options.

While I'm absolutely not very good with Linux there is fantastic documentation and support (e.g; I couldn't get a game to launch this morning and within an hour I had someone tell me what was wrong, how to fix it and it's working now).

I wish you the best of luck with your issue, I'm sorry this is more of a sales pitch of Linux than actual support but I'd figured I'd offer an alternative solution to your issue if you're unable to find one.

Best of luck!

I think Zekiran refered to Steam itself. It works fine, likely.
What I refered to what Steam Friends which is HTML/Web based nonsense loaded it through the Steam Browser (chromium).

I would suggest you to try Firefox and run Steam Friends in that browser. It should work, and if that works, its very likely the SSL certificate issue I mentioned.
(small edit: I somehow forgot the part you mentioned you already confirmed this.)

The reason why Firefox works is because its programmed to trust newer root certificates and yes, these 'trust issues' can be different per program. Although they tend to use the same store, the main 'database' basically that is used by your pc. You can manually install a few certificates yourself that could potentially replace it or force your system to trust newer certs, but idk if that will extend to the chromium browser used by the Steam Client.

The problematic certificate is DST Root CA X3, which has two providers. (you can look it up in certlm, which provider your system has). This certificate recently expired.
There are a couple of newer ones. Updates normally ensure that the newer ones get trusted. (they may already be installed.)
but yeah.
anyway firefox will trust newer certs.

Edit: fyi
Windows 7 has many versions.
Most people that converted their Windows XP SP2 machine went to Windows 7 and stayed there.
Its possible its due to that. At its core its still using elements and settings of Windows XP SP2.
Clean Windows 7 systems will not likely be affected, but upgraded (to windows 7) will.

Edit 2 :
I had to look up the official route on how to install them, which is a bit complicated, but still. Here's a very late edit as such.

First, if anything, just check 'certmng' and see if you have ISRG Root X1. If not, you may need to download and install it.

Grab at least: https://letsencrypt.org/certs/isrgrootx1.pem
Some people have been recommending grabbing two more from letsencrypt.
https://letsencrypt.org/certs/isrg-root-x2.pem
https://letsencrypt.org/certs/lets-encrypt-r3.pem
I don't have the last two.
You can also get the one from IdenTrust https://www.identrust.com/support/downloads
(You need the commercial root certificate for individuals, if you get the one from there. xd
installing this one is also easier. Just right click, install, etc. Anyway...)

The following steps are done at your own risk. I recommend scanning files and such just to be sure, and such. Anyway... to install the certificates:

Open MMC (Microsoft Management Console)
press CTRL+M
Select Certificates
Click Add
Select Computer Account
Select Local
hit OK
Open the directory tree and right click on Trusted Root Certification Authorities
mouse-over All Tasks, hit Import
follow the instructions there to import the certificates.
Once done, go back to MMC

Hit CTRL+M again and add the group policy object editor
Select the Local Computer object and hit okay.
Go to: Local Computer Policy > Computer Configuration > Windows Settings > Security Settings > Public Key Policies
Here, double click on Certificate Path Validation Settings and then hit Stores tab
Check Define these policy settings
Check Allow user trusted root CAs to be used to validate certificates
Check Allow users to trust peer trust certificates
Make sure under "Root CAs that the client computers can trust" that Third Party and Enterprise Root CAs is selected.

Hit Apply, OK. You're done.

Edit 3: It should now work normally. If not, you may need to remove the old expired certificate. Let me know the results ;p

Edit 4: (11 hours after Edit 3)
I uh... realized you will also need Baltimore CyberTrust Root which you can get here: https://www.digicert.com/kb/digicert-root-certificates.htm
its because of cloudflare which steam uses instead of Akamai. If you have Steam through cloudflare then this is the root cert you mainly need instead of isrg root x1.