|I would suggest your router is probably on it's last legs and in need of replacement.|
You could try power cycling it (ie: shut it off, wait 10 second, then plug it back in) and see if that doesn't fix the problem. If not, you could try resetting it to factory defaults and see if that fixes the problem.
If neither fixes the issue, it's toast, time to buy a new one. If power cycling works, it'll likely only work for a while and then it will stop working properly again. The same is true for resetting...if will likely only work temporarily, if at all.