Airport Extreme making my Apple TV 2 constantly restart.

Last night we noticed that iTunes wasn't able to connect to the ATV2. Everything else worked fine except this so I tried a reboot and ever since then, the ATV2 has been on a continuous loop of restarting and turning off before I can do anything. I tried unplugging the power, I tried plugging it into my MBP and doing a restore but, of course, Apple is no longer signing the software so I can't do that. Eventually I realised that, if I disconnect the Airport Extreme, the Apple TV will stop rebooting but of course, I can't use it without an internet connection. Plugged the Aiport Extreme back in and the problem immediately restarted.

So.... Any advice?

Thanks,

Chris