I did following after goggling and reading some topics but finally certificate renaming works.
1) Check all services
2)Enabled TCP/IP in SQL Server Configuration
3) All Firewall are off
4) Enable Remote Connection
5) SQL Server Browser Service is enabled
6) Created exception of sqlbrowser.exe in Firewall
7) Protocol Encryption set up off, checked other Network protocol settings but didn't work.
8) I also tried Surface Area configuration for services & connections
9) moved TCP before named pipes in the protocol order