rocman3 :
Blizzard support said its about my ISP but if its my ISP why i can log in just fine from another computer?(with the same modem) host and dns settings are untouched.
Anyone knows what might be the cause?
It could be a setting in your firewall or with your antivirus programs. Typically, when Blizzard game are installed it automatically enables their games to pass through these programs without issue, but from time to time installations can go bad and you need to fix them manually. All you should need to do is go in and give permission for WoW, D3, or whichever game you intend to play to pass through your protections on the PC. If that doesn't work, then you can try to uninstall/reinstall the desktop application and the game(s) in question. Outside of that, I'm not sure it would be something on your end.