If you go to Run and type "cmd" hit ok. Then type IPCONFIG and press enter, write down what your default gateway is.
For example for me:
Code:
C:\Documents and Settings\Owner>ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . :
IP Address. . . . . . . . . . . . . : 192.168.1.3
Subnet Mask . . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . . : 192.168.1.1
So, every computer on my network will have the Subnet mask 255.255.255.0 and the default gateway of 192.168.1.1. But each computer will have a different IP address, like my notebook might be ".4" and my second desktop might be ".2". Occasionally what happens is if stuff gets turned off and on a lot, the network card inside a computer tries to remember what IP address it was given sometimes, and request it. But its possible the router has given out that number to a different machine. The router is supposed to be like oops no, but sometimes it will try to give out the requested number again, and now you've got 2 machines with the same IP.