Is it getting an IP address from your router's DHCP? Open up a command prompt and type "ipconfig /all > c:\ipconfig_results.txt" (without the quotes) <enter>. Then type (in the command prompt) "notepad.exe c:\ipconfig_results.txt" (again w/o quotes) <enter> and copy paste the results here.
Windows IP Configuration
Host Name.................: 08VEIREB
Primary Dns Suffix........:
Node Type.................: Unknown
IP Routing Enabled.......: No
WINS Proxy Enabled......: No
Ethernet adapter Wireless Network Connection:
Connection-specified DNS Suffix .:
Description...................: Atheros AR5007EG
Wireless Network Adapter
Physical Address............: 00-24-2B-09-CD-F4
Dhcp Enabled.................: Yes
Autoconfiguration Enabled.......: Yes
IP Address.....................: 192.168.1.4
Subnet Mask.....................: 255.255.255.0
Default Gateway....................: 192.168.1.1
DHCP Server......................: 192.168.1.1
DNS Servers...........................: 192.168.1.1
Lease Obtained..........................: 11 December 2009
23:06:27
Lease Expires...........................: 12 December 2009
23:06:27
Ethernet adapter Local Area Connection:
Media State.............................: Media disconnected
Description..............................: Realtek RTL8102E Family
PCI-E Fast Ethernet NIC
Physical Address............................: 00-23-8B-3C-0D-61