If you are experiencing problems with your WiFi signal dropping or behaving erratically, you may be operating another device that is using the same frequencies and is competing for space in the frequency spectrum. Many WiFi routers operate around 2.4GHz, and there are a LOT of other devices that also use the same frequencies, like wireless phones, wireless mics, Bluetooth devices, etc.
While we really can't troubleshoot your WiFi network for you, here are some articles that might point you in the right direction when troubleshooting WiFi issues and maybe help you understand the technology better: