Respected Manorajan,
Me too had d same problem but i solved it later on myself.
Here's it how to :-
1- Make sure u have intel network driver installed i ur windows it pc. Download it ( on any other pc and transfer and install it into this one) and install it in ur respective windows 8 pc. Here's the link to download it :- http://drivers.softpedia.com/get/NETWORK-CARD/INTEL/Intel-Network-Adapter-Driver-172-for-Windows-8.shtml
Den download realtek lan driver from here install it http://drivers.softpedia.com/get/NETWORK-CARD/REALTEK/Intel-Realtek-LAN-Driver-80030730-for-Windows-8.shtml..if in installing theres any error ignore it..dont panic and reinstall..as it will already be installed
2-unplug your LAN cable and wireless connection
3-Go to network and sharing center den on d left side click on change adapter settings left clik on intel network adapter
4-Go to "Ethernet Adapter local area connection" properties and deselect '' Internet Protocol Version 6 (TCP/IPv6)''
5- select **"**Internet Protocol Version 4 (TCP/IPv4)"
And press Properties button
6- select "Use the following IP address:" option and set this ips
IP= ''ur ip address''
subnet mask=255.255.255.0
default gateway = your router ip (you can recheck all dis from any other pc having a successful conection wid dis same one by checking the properties of d connection or from any smart phone like any iphone or android mobile if it is used as a wifi too by seeing staus/properties of ur respective wifi name )
7- from second section select "Use the following DNS server addresses:"
set**"PreferAlternate DNS server:"** your router ip which u entered in ''default gateway'' above. press ok and try to connect through lan then wireless
If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
The Network Connection Properties dialog box
4. To specify IPv4 IP address settings, do one of the following:
7. To change advanced DNS, WINS, and IP settings, click Advanced.