I have a version 1 WRTG54S-- fully updated-- that has been doing just fine for several years in my home office. Recently, WiFi signal strength has dropped off by about a third as has range. This occurs on several different computers, WiFi devices, etc. Running WPA2 security, channel 6, SSID disabled, MAC filter enabled. No recent changes in equipment, software, location, or my house/furniture. Is is just getting tired and I need a new one-- or is there some fix I can apply?