O2 Broadband (IRL) - problems!!

[downgirl]

Technological help needed!!  Got an O2 broadband modem last week because the internet in our apartments is really slow.  Has been working fine until yesterday and today, it is only picking up O2 GPRS not O2 broadband (light is green not blue) even though it has been in exactly the same place all week, O2 phone has perfect signal and my roommate who also has O2 broadband brought in his computer and modem and it is working fine...any ideas why mine isnt??