Ok, the wireless router I am using will randomly shut off. It happens to all three of the laptops in the house that use the router. All are different brands running Windows 7 and the drivers are updated. Sometimes the wireless will work for hours but then other times it will lose connection, come back, lose connection and the pattern repeats.
Oddly enough, sometimes when the wireless stops working. I check the internet access icon in the bottom right of Windows and it either says it is trying to reconnect to my network but sometimes it will be trying to connect to another router somewhere in my neighborhood. Sometimes it will give up connecting to that other router and go back to mine and connect fine and other times I have to tell it too disconnect from that other router and click my network again.
It sounds like the wireless radio in your router is malfunctioning -- the next time it does that you can check for a wireless signal from one of your machines by running inSSIDer (a freeware app). If you don't see a signal on your channel and SSID, it isn't there for at least a short time.
The loss could be due to the router itself (more likely) or some strong source of interference very close to the router (like it's sitting on top of a microwave oven that someone turns on ).
you can try changing the wireless radio frequency the router uses. if there are a lot of devices using that part of the 2.4Ghz spectrum it can cause intermittent connectivity. For example if your neighbors have a lot of wifi routers in range, cordless telephones, baby monitors, etc can cause interference.