Internet Works on one PC but not on the Other - LINUX(Ubuntu)

This is similar to the previous article, the difference being that the steps in this article is for linux users especially ubuntu users.
If you have one PC and you have internet problems then there could be many reasons for it, but incase you have multiple pcs at home and all other pcs have internet access and LAN access and there is this one pc which just wouldnt work, then fixing it could be a little easier.
Firstly, you need to make sure that hardware and connection wise ,everything is fine.Typically it is an ip address issue which can be easily fixed by entering a static ip or sometimes failure to get a DNS server too, which again can be fixed by entering the DNS servers manually, so this solution takes care of both.Most of the time the reason why internet or LAN doesnt work in a pc is due to failure of getting an ip address.So here's how you go about doing it:
NOTE:Presuming that your pc is connected to a router of ip address 192.168.1.1 ..hence giving pc ip as 192.168.1.10 , if it is connected to a router of ip 192.168.0.1 , then set pc ip as 192.168.0.10

Step 1 : Go to System->Administration->Network

Step 2 : If you are connected to your router via wireless then follow step 3 if not move to step 4
Step 3 : Since you are connected via wireless, you need to know which interface is wireless.For this, go to your terminal and type iwconfig . You should see an output similar to this

lo no wireless extensions.

eth0 no wireless extensions.

wlan0 IEEE 802.11g ESSID:"WIFINAME" Mode:Managed Frequency:2.462 GHz Access Point: 00:14:6C:19:66:D8 Bit Rate=54 Mb/s Tx-Power:32 dBm RTS thr:2347 B Fragment thr:2346 B Power Management:off Link Quality:90/100 Signal level:-38 dBm Noise level:-96 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0

Now in my case, wlan0 is my wifi interface as it HAS a wireles extension
Step 4 : Since you are connected via LAN then your interface would mostly be eth0.
Step 5 : Now after knowing which interface you have go to the correct interface Properties(System->administration->network)

Step 6 : Now Uncheck "Enable Roaming Mode" and Select Configuration as "Static IP Address" and enter the following
IP Address : 192.168.1.10
Subnet Mask : 255.255.255.0
Gateway Address : 192.168.1.1

Step 7 : Click on OK and close other windows and you should have a working connection.