I made changes in WinBox (Router OS) in local interface. The below changes i made:
100mbps/full duplex
100mbps/half duplex
10mbps/full duplex
10mbps/half duplex
Auto detect
During these changes the mikrotik automatically disconnected. whilst I tried to ping our mikrotik server 192.168.9.1 then its ping timed out and do not connect. any one who know about this problem. please help… thanx 
Your winbox connection was through the interface you played with? Do such test when connected over another interface! duplex and speed negotiation depends on several factors, for example the device on the other side of the cable. 99.99% of cases everything is Auto and/or 100M full duplex and works perfectly. You don’t need to change it, unless someone set it to low. You can simply check if its OK (100M full duplex, 1G full duplex etc) when you doubleclick on the itnerface itslef in WinBox and check the status there …