Netgear WPNT834 wireless not working

My router has developed a problem with wireless acess. When I view the available networks, on any system with wireless capability, I see all my neighbors, but can only see my router occasionally, and cannot connect through it. The settings are WEP, shared key, 64 bit, running on channel 6. It used to work, but for some reason, it doesn't show up in the available list anymore. I've turned the unit off overnight, but the problem is still there.

Does wireless gateway functionality fail? Is there any way to fix this?
I cannot pick up an internet connection from this router, through Belkin Wireless airstation(c) dongles, but my dongles can pick up everyone elses connection. sometimes i find it during the evening, but this is a problem as i need the internet during the day also. please help, thanks