Can't join any server on TF2, HL2:D or HLD:S

[Haze]

When I try to join a server, appears the message: "Disconnect: An issue with your computer is blocking the VAC system. You cannot play on secure systems." I tried everything that the Support tells to do, and nothing works. How can I fix this?

[ReBoot]

Everything? Have you also followed that last part about conflicting processes?
Mind showing a list of the processes on your system?

[Haze]

Yes, everything. Nothing worked.

I don't know how to upload screenshots here, so I'm just gonna write down the processes.

atieclx.exe
chrome.exe
chrome.exe
chrome.exe
chrome.exe
csrss.exe
dwm.exe
explorer.exe
flux.exe
HpqSRmon.exe
HydraDM.exe
jusched.exe
msseces.exe
RtHDVCpl.exe
Steam.exe
steamwebhelper.exe
steamwebhelper.exe
taskhost.exe
taskmgr.exe
winlogon.exe

When I first got the error, the firewall blocked hl2.exe. It's allowed now, but I still get the error. I don't know if this is related.

I tried restarting Steam and the computer many times and when I do this, two things can happen:

1. I join the server normally and play. About 5 or 10 minutes later, I get the error and I'm kicked of the server.

2. I try to join a server and appears "Interdimensional timed out". Then I try again and get the VAC error.

[ReBoot]

I bet whatever you want there's more. I think that those are only your user processes but not processes running with administrative privileges.
Also, have you tried it in safe mode?

[Haze]

Solved. I did this: https://support.steampowered.com/kb_article.php?ref=2037-QEUH-3335