Do you have a modem or a router (and if so what make)? How many PC's have you got connected - if it's more than 1 then you have a router. If so, can you connect to the router,
type 192.168.0.1 in the address bar in Internet explorer. (might be 192.168.1.1)
You can confirm the above address by typing in
ipconfig from a dos window (click 'Start', 'Run', type 'Cmd' and click OK) and typing in '
ipconfig' The address you need is the 'Default gateway'. Still at the command prompt type in 'ping 192.168.1.1' (or whatever the default gateway is.) It should come back saying 'Reply from....'. If it says 'Request timed out'. then your router probably isn't working. If it says reply from, then it's probably a BT/Orange fault. (That bit depends on whether you're on an unbundled loop)
If not, reboot the PC and call Orange.....