Just reset the 54g according to the manual (usually the 10+ second hold of the reset and then change the few items custom to your setup. If it's a setting then it will work again.
For the past week, my router is periodically dropping the signal. It affects every device in the house, all of which connect wirelessly.
When I disconnect and then reconnect the router from the modem and the power, it works again - sometimes for a short period, sometimes for a whole day.
I'm assuming there is something wrong with the router, or the connection between the router and modem, or perhaps some wireless setting (?)
Anyway, we have two desktops, one running Windows 7 and one running Vista. We also have two android phones and an android tablet (all Jelly Bean), and a Nook HD. All devices are affected.