The issue got resolved.Though windows firewall was disabled ,symantec endpoint protection firewall was active and it had blocked Winscp.I allowed winscp and now everything is fine.
I have trouble connecting servers through winscp in my current laptop. I see that I can connect all the servers in my old laptop. I went through all fAQ but didn't help. I uninstalled, reinstalled and tried with different version too.I also tried adding winscp.exe as exception in firewall and presently firewall is disabled. All my winscp settings and firewall settings are same as my old laptop. I can connect to the servers through putty.
I get Network error :connection to "xx.xxx.x.xxx" timed out error.