Wireless Networking, Virgin (UK)

Hi, im mainly looking for advice on wireless networking, how hard is this?! I have two laptops, one a year old with ethernet and wireless capabilities and a new machine literally bought yesterday with the same.
The old machine has been connected to via ADSL Speedtouch USB modem to Virgin Net (ISP) for months, and has been nice and problem free. No messing with settings or anything, once software was installed it worked!
Anyway, as stated, have bought a new machine, and also plan to add an Xbox 360 to the equation in the near future, so, i bought a Philips SNA6500 Wireless Modem Router, along with the new machine.
Problem number one: When connecting router to phone cable ADSL light comes on fine, connect it to the old laptop to configure firmware to the ISP, and it pulses from sold green to off, every second. When trying to install software, an error is reported and action of checking the cables are connected properly is suggested. However, in network connections the LAN connection is active, working fine, and has a speed of 100mbps etc. So..what gives? Intially this was thought to be a problem with the router, but connecting it to the new machine and going through the same process has no issues. SO its between my older machine and the router. Driver problems with the ethernet card? Secondly, the old machines wireless setup fails to recognise the wireless network provided by the router, whereas the new machine detected it straight away from initial switch on.

To clarify: problem = compatability between old machine and new router. Solutions? Advice?

Second problem: when attempting to configure the firmware via the NEW machine, i encounter a list of UK ISP's to auto configure from, suprise suprise mine isnt on there. So, im confronted with a situation whereby i have to manually enter things like 'Protocol' 'MTU' and 'VCI' etc These are values i have no idea about, what-so-ever. How can i find these out? is there a program i can download that will detect these settings when the old machine is again connected via the USB modem originally used, as i am now.

Future issues: once the router is configured and a connection is made to the broadbandm, lighting up the 'on-line' LED on the router, what next? How do i then configure the new laptop to connect to the internet via the wireless connection to this router?
Furthermore, the old machine, having updated drivers to the most recent ones i can find for both ethernet and wireless cards/controllers, if these still fail to interface with the router, will the free dongle that came with the philips SNA6500 work as a final resort? will i lose any speed? how easy are THESE to configure on a machine that has been, up to now, running off the USB modem?

I know this is a lot, but im confident its simple to those that have the know how. Any advice would be greatfully recieved.