Unauthorised access to my wireless network?

[#1]

Tried raising this with PN's technical staff but not getting a helpful response apart from "Change your pw".
Checked out my wireless setup recently and was astonished to find sitting there a completely unknown and unrecognisable device with the reference "Unknown-7c-6d-62-0d-06-bf". Apparently I've given it authorisation but I haven't a clue what/who it is. Every time I check it seems to be inactive.
How can i find out any more about it?
Can I prevent it from accessing my wireless network without changing my pw? Surely if I can authorise it I should also be able to "unauthorise" it?

[#2]

click on Unknown-7c-6d-62-0d-06-bf, then up top click configure and make sure Allowed on WLAN is unticked?
This should prevent it logging on to wifi if i'm right 

[#3]

If it helps to identify it,with a MAc address starting 7c-6d-62 it's an Apple device!

[#4]

Hi there,
You could use MAC address filtering to only allow specified devices you've approved to access your network.
I would seriously recommend changing the password for your network though as the "unauthorised" device must have been able to find this out in order to connect to your router.
Adam

[#5]

click on Unknown-7c-6d-62-0d-06-bf, then up top click configure then try clicking delete and see if that works
If it does then click on the wireless LAN and then configure and change it to new stations are not allowed

[#6]

Are you using WEP or WPA security on your router ?
If it is WEP then change asap as it is very insecure.

[#7]

Quote from: picbits

Are you using WEP or WPA security on your router ?

Hi picbits - thanks for your reply... my router's set to WPA

Quote from: Oldjim

click on Unknown-7c-6d-62-0d-06-bf, then up top click configure then try clicking delete and see if that works If it does then click on the wireless LAN and then configure and change it to new stations are not allowed

hi oldjim and thesawdust .. sounds good will try that as it sounds the easiest and simplest option 

Quote from: _Adam_Walker_

I would seriously recommend changing the password for your network though as the "unauthorised" device must have been able to find this out in order to connect to your router.

  Hi Adam - yeah I do take your point. I'll try oldjim and thesawdust's simpler option first. Then, if it reappears I'll know someone is snooping and change the pw.
Cheers everyone!

[#8]

I'd change the security to WPA2 whilst you're at it ;).

[#9]

@ Susie/Alec R
I've not done that previously for the simple reason that PN's guidance on setting up the router says the following:
"Only change to WPA2 if all your computers or devices support it."
Now, I haven't a clue whether my PC (9 years old and running Windows XP OS) actually can support this. And of course PN doesn't tell you HOW to find this out! Do they seriously think we should know?
Frustrating or what?!

[#10]

Have you had the same wireless card in it since you got it 9 years.
WPA 2 got certification 9 years ago, but has only been mandatory in products for the last 7 years. chances are it is NOT WPA-2 compatible but depending on the make/model of the wifi card there may be a slim chance it is.
I would find it very unlikely for there to be an actual intrusion on your wifi network, are you sure no one has an apple based product, I-Phone/I-Pad/I-pod or Macbook laptop? anyone you might've given the key too?
If you are concerned about it I would recommend changing the password as soon as possible, as for tracing the device, their isn't too much you can do yourself in that respect unless it is active on the network and then, you need to know what your doing.