Ich zocke gerade...

[deXXXa]

Immer noch die gleiche Meldung! Schreibe mal den Support an

Hast du Kaspersky? Falls ja: Könnte daran liegen. Einfach ausschalten und Steam installieren.

Edit:
Uninstalling Steam - How To's - Knowledge Base - Steam Support

Manually Removing Steam
Warning:
Dealing with your registry requires extreme care. Do not delete anything in your Windows registry that you are unsure about. For this reason, we suggest you only use this option as a last resort.
Exit Steam.
Navigate to your Steam directory. (Typically C:\Program Files\Steam or C:\Program Files\Valve\Steam
If you wish to save your game files for a future installation of Steam, copy your steamapps folder outside of your Steam directory.
Delete all of the contents of your Steam directory.
Go to Start > Run and type in regedit.
For 32-bit operating systems:
In the left-hand column of your registry editor, navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Valve\.

Right-click on Valve and select Delete.

For 64-bit operating systems:
In the left-hand column of your registry editor, navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Valve\.

Right-click on Valve and select Delete.
In the left-hand column of your registry editor, navigate to: HKEY_CURRENT_USER\Software\Valve\Steam.
Right-click on Valve select Delete.
Close your Registry Editor.