Throw it in the bin (or consign it to the loft) and buy a real one! They are good for some things, and not so good for others.
Some settings you can change, others you cannot. I never use the BT supplied router on any BT internet connection - they are just too inflexible.
For instance, you cannot lock down TCP port 25 outbound from certain IP addresses - it is either open or closed. Not very useful in a business environment.
They offer two wireless connection - the Business Hub one and the other one. Both offer different IP addresses depending on the one you connect to, so if you cannot see computers on your network and are wondering why, it is because you are not connected to the Business Hub wireless (which gives out the same IP addresses as the wired connections).
: )