Wireless Woes with O2 W II or Lapdog?

[Tricky]

Hi all!!!

This, my friends, I think is a tricky one.... hope you like a puzzle :-)

I will try and make this as brief as possible, so you don't switch off this post when you see how big it is!! Do do have all relevant technical details if need be but hopefully someone will know whats up!

My dad has a Wireless 02 II router TG585v7 on 7.4.20.3
It has been working fine for about 18 months
He has two laptops using wireless an older HP on XP and a Sony Vaio on XP Media Center and a wireless internet radio.
These have all been working fine for the same amount of time.

Recently, however the Vaio Wireless, which is a Intel® PRO/Wireless 3945ABG seems to connect for approx 1-5 minutes then drops. Throughout this time neither Internet Explorer, NSlookup, Firefox can resolve names.
The DNS Server and Default Gateway are set to 192.168.1.254 and it has been given an IP address by DHCP 192.168.1.65
When the link drops the software shows problem next to the router but still shows the IP address even if I refresh the screen. There is a Disconnect button available on this connection.
The Wireless Radio and the HP, although older than the Sony, continue to work fine?

When I go onto the router and take a look I have changed the wireless channels from Automatic, to numerous different channels and this makes no difference. I have also forced the connection to b and to g and the radio and the HP continue to work fine in any combination but the Sony gives the same results.

One thing that was a bit of a concern, when I look at the interface list on the 02 II router the MPS changes? I have seen it as low as 11, 18, 24, 36, 54. I can see this change when I hit the Interfaces button. It doesn't change all the time but at a guess I would say that it "might" coinside with the drop on the Sony.

I thought that either maybe the Sony was more sensitive to the speed changes or it's trying to connect slightly higher so suffers more?

I know this sort of issue can also be contributed to big tellys, phones, or any other interference but nothing has changed on this front in 18 months and the other two devices seem to work fine.

I took the Sony home, and connected to my router wirelessly and was surfing the internet in 2 minutes using the same security settings, WEP 64, as the 02 at my Dad's, but my network is 192.168.55.x

I can see that there is a 7.4.20.4 release of the firmware but am pretty lothed to go changing things if i know the other devices are all ok?

The Sony works fine if I plug it into the router via Ethernet!

Turned the firewalls and antivirus off completely from the services rather than through the software interfaces, uninstalled the antivirus at one point, all seeming pretty needless if i know it works on mine at home?!?!

The only other thing that I could think of is that there was something blocking access on this machine from the 192.168.1.x subnet from DNS requests, but again, this wouldn't cause the drop?

I even resorted to upgrading the wireless driver on the Sony, even though i know it works ok on the older version of the driver on my network at home.

Any ideas, had some long, tired nights and its annoying the monkey out of me!

(obviously monkey substituted for a ruder work but I have agreed to terms and conditions of posting!)

Is it just.... in technical terms.... broken?!?!

Thanks Alllll!!!

Rich