changes to domains, such as changing name servers can take up to 48 hours. Most of the time it's only a matter of an hour though.
You could try to flush your dns cache to force your computer to look for new information on what IP the domain is located at.
If you need information about how to flush dns cache you can find that here for a few operating systems:
http://kb.x10hosting.com/questions.php?questionid=16
welli cleared it but when ever I try to access my site in FTP client it says my password is wrong
This is error
Status: Connection established, waiting for welcome message...
Response: 220---------- Welcome to Pure-FTPd [TLS] ----------
Response: 220-You are user number 146 of 500 allowed.
Response: 220-Local time is now 18:25. Server port: 21.
Response: 220-This is a private system - No anonymous login
Response: 220 You will be disconnected after 3 minutes of inactivity.
Command: USER ********
Response: 331 ********* OK. Password required
Command: PASS ********
Response: 530 Login authentication failed