If the problem is due to your Oracle Linux Firewall, you can try to disable it to see if it help by entering the following command as root:
service iptables stop
Please note that neither VirtualBox nor Windows are within the scope of this forum. I suggest to see the VirtualBox documentation, which explains the various network adapter types and their limitations. The NAT adapter, for instance, is for outbound connections only, effectively hiding the guest OS behind the virtual machine network adapter.
You might find this helpful
see: http://edstevensdba.wordpress.com/category/personal-test-systems/]configure the Virtual Box Network)
or this, which I discovered after writing the above, but says pretty much the same
It is not possible to troubleshhoot your networking issue beyond the guesses that have been made. Please provide some useful info about your TCP/IP configuration. Ping is limited to ICMP and not necessarily the right tool or providing the necessary info to troubleshoot your Internet connection. If you are using indeed the NAT adapter, make sure the guest OS is using DHCP and the network is started. You will most likely find your answers browsing the VirtualBox documenation.
i am unable to access your link , i have tried the same as per the second link , still i face the same i couldnt connect to net using the terminal.
"Unable to access" and "couldnt connect" are devoid of actionable information. If you are able to get to this forum, you should be able to get to the links I provided.