Im going to assume your modem connects fine(steady lights)...
Control Panel- Network Connections- Local Area Connection(if you dont see this, you may need to create a new one by using the wizard)
Select "local area connection"
Highlight "Internet Protocol(TCP/IP), now go to properties.
Select... Obtain IP address automatically and Obtain DNS server address automatically
Ok and Close.
You should be able to connect now, if not...
Start- run- Cmd
ipconfig/release
After typing this and pressing enter, type in...
ipconfig/renew
If that does not work, restart pc and turn off modem. When you see the windows logo, turn on the modem. When you reformatted, did you install your network drivers?
Right click "My Computer" - Properties- Hardware(TAB)- Device Manager
Do you see any exclamation marks?
BTW, haven't been playing because I'm on DIAL UP!!!!!!!!! LKDJLSKJD