Question: I bought a new desktop PC (eMachine ET1331G-03W from WalMart) with windows 7 installed, but I can not access internet by connecting to my existing wireless router(LinkSys BEFW11S4) with wired cable. Though all other existing desktops and laptops have no problem connecting to the same router. However, the new desktop PC works fine and able to connect to internet if I bypass the router and directly hook up with the cable modem.

At new PC when connecting to the router, I got the below information by typing ipconfig, the IP address looks wrong to me:

autoconfiguration IPv4 Address: 169.254.71.140
subnet mask: 255.255.0.0
default gateway: (empty)
NetBIOS over Tcpip: Enabled

Typing ipconfig at all other desktop and laptop have values like below, which are good to me:

```
    Connection-specific DNS Suffix  . :
    IP Address. . . . . . . . . . . . : 192.168.1.140
    Subnet Mask . . . . . . . . . . . : 255.255.255.0
    Default Gateway . . . . . . . . . : 192.168.1.1

```

The wireless router was on 192.168.1.1, I do not know why the new desktop got 169.254.71.140 IP? It should have something like 192.168.1.xxx, and it was configured to automatically get IP by DHCP.

I have tried to switch cables,power off cable modem, router and reboot new pc many times and got no luck. So I believe this is only an issue related to router or new pc configuration.

Can someone help me figure out the issue?

Answer: 
The IP address that your computer got is called an [APIPA](http://msdn.microsoft.com/en-us/library/aa505918.aspx) address. Most likely your new computer does not have DHCP enabled or your router has run out of DHCP addresses. If you need help checking those values let me know.
thanks every one for the answer. I tried the static IP, still does not work. I suspect the router may not support windows 7 64bit. The other PCs connecting to the router are all Win XP. I will get a Win 7 certified router, and try again.