majid,
I'm sorry to hear you're having such a bad time here 
Can you tell me what type of connection you have? Is it cable, usb wifi dongle? or wireless?
Which browser and version are you using?
How old is your computer?
Have you cleared your browser cookies recently?
If you click on the link below, then refresh your browser, re-login to the site and try live chess then.
http://www.chess.com/clear_cookies.html
Dear chess.com i love your site and i have switched to your site after 12-13 years p[laying in other chess sites, i am sorry to bring this to your attention but there are serious problems with your chess site. Almost every single time i am there either my screen freezes or have similar problems such as slowing dow my whole system, freezing for short or so long that at some stage i see the need to switch off my pc manually.
I do understand you are doing your best but let me tell you that i along side may be so many other players have defected to from other sites with persisting issues.
many thanx
majid100