Dupa un mic search pe google am gasit 2 threaduri foarte folositoare dupa cum urmeaza :

1)

Originally Posted by jessman
Guys i've discovered the solution to this problem. All you have to do is find the config.cfg file and delete it. You can find this file in three diferent places:
1st Open Valve\steam\steamapps\Your accont name\Counter strike\Cstrike
2nd Open Valve\steam\steamapps\Your accont name\Counter strike\Cstrike_...
3rd Open Valve\steam\steamapps\Your accont name\Counter strike\valve

Delete all three config. cfg and the problem is solved. This has to be done with the game off. After doing this, start steam, start counter strike and you will be able to enter any server, you just have to configure your game option again like your name and things like that. I hope i've been useful. Have fun guys.

I Forgot to say something, the steam will create another config.cfg when you start the game again so don't be afraid to do it, i've done it and it worked i had this problem too.

2) Counter-Strike: Unknown HLTV client type | SK Gaming