Why does my Wi-Fi turn on and off?

I'm having problems connecting to the internet both with my laptop (running windows 7) and my iphone 4s.

1. If i plug an Ethernet cable into the laptop it works fine.
2. Sometimes the Wi-Fi works fine on the laptop but other times it seems to randomly stop working
3. Sometimes the Wi-Fi works fine on the iphone but other times it is 'unable to join the network'.

i have rebooted both laptop and phone multiple times as well as the router but it doesn't seem to solve the issue.

Anyone have any thoughts?!

The problem is probably in your router. It might be broken, and thats why it does that.

1)You may be getting interference from neighbouring wireless signals. Change the broadcast channel on the router to channel 11 or 2 steps higher or lower than the current. You can download netstumbler or inssider (google them) and they will display the broadcast channels of any neighbouring Wi-Fi networks

2)Turn off any baby alarms cordless phones wireless doorbells as these use the same 2.4Ghz frequency

3)Update the firmware of the router and drivers for your PC/laptop

Happens to me, changed my router and there was no problems afterwards

Routers seem to only last a few years, and when they fail they often do really odd things rather than just stop working. Replace your wireless router.

David is correct. If you have a smartphone download Wi-Fi analyzer to check which channel is best suited for your router.

You might need to be closer to the Wi-Fi to get better connection.