can you loginto your O2 router if its the White O2 supplied one. open internet Explorer and type in the address bar at the top 192.168.1.254
then when the O2 settings home page opens for your router can you click on Broadband connection in the Left hand side pane. then it changes the window and you will see Bandwidth Up/Down
Can you mail back with the figures it gives you for up and down.
Also post back the following info about your machine: Which windows, How much memory, Processor.
Also make sure you have Java & Adobe Flash player installed. Look in the add/remove progs in control panel for this.