4 Wireless computers, but random connection drops

I have 2 laptops and 2 desktops (with wireless pci adapters) connected to a netgear router.

The problem I have is that the connections are very unreliable, and one computer will randomly drop the connection and not be able to get it back for some time. Sometimes even 2 computers will have the problem, although all 4 have been able to connect at once.

The desktop used primarily for gaming disconnects for a few seconds during the middle of games (TF2, Left4dead, etc), but the connection usually comes back quickly. Even the laptops have experienced the problem, and they will be able to pick up the signal and connect to LAN but not the internet. The connection of all the computers is 3+ bars at all times, but for some reason they will try to connect and be unable to.

I believe the problem must have something to do with IP addresses getting mixed up, as disconnecting and reconnecting to the router can sometimes resolve the issue, but that doesn't explain why the computers randomly loses their wireless signals. Would anyone care to assist me with my problem?