Why does my Sky broadband keep kicking my Apple and Windows devices off?

[SamuelCB]

Ok so I have recently joined Sky broadband and I am getting fairly good speeds for my area. When I am using my broadband on a single device it works fine and it also works fine when using it via the ethernet cable.

My problem is that in my house I have a iMac, 2 iPhones, 2 iPod touches, 2 windows laptops, an Apple TV, a nintendo Wii, a Mac book and a Xbox 360. (A lot I know :P) so when I have one of these devices connected it is fine, however as soon as I connect a few of these devices then everything just goes completely wrong!! When I am downloading on iTunes on my iMac then NO other devices can connect to the wireless router, and if I connect a windows computer to the network it seems to kick all the Apple devices off and vice versa.

I am studying IT and Networking at college so I am not a complete noob, however this one has me baffled. I do not have the default SSID or security code set on the router as I have changed them but the network key is still set as WEP and UPnP is turned off. If anybody has any idea what is going on then please let me know asap .........Thanks!!

[PaulSky]

You have checked obvious things like manual IPs I take it, this shouldn't happen obviously, we have PCs and Iphone devices all hooked up at the same time so this is definitely not normal behaviour.
How many of these items are wirelessly connecting at any one time?

[BritBrat]

Have you tried setting reserved IP's in the router for each device?

Why are you using WEP as I thought that was quite easy to crack?

What IP range is allowed in the Router DHCP Server have you restricted it from default?

[IWasNotTheEnemy]

I think they mean WPA as unless they've manually changed it won't be on WEP (although some old Macs only work on WEP from experience)