Changing the password in SQL Server was much easier. You just type the following thing and password for the account is changed:
sp_password 'Old','New', Account
But this dont work for Sql Server 2005. Initially I thought whats worng with the SQL Server, but later I realized that it may be different for the two versions. At last I found it and here it is:
ALTER LOGIN Account_Name WITH
PASSWORD = 'New_Password'
OLD_PASSWORD = 'Old_Password';