Frequent Wireless Network Dropouts

I have a wireless network consisting of a Netgear WGR614v2 Wireless Router connected to the internet with a Siemens Speedstream 4200 ADSL Modem and 2 desktop computers each with a D-Link AirPlus G Wireless Network Adapter.

The network drops out several times a day (the computers are suddenly unable to detect the presence of the network) and the only way to reconnect to the network is to unplug the power from the router and plug it back in. Some programs seem to make the connection dropout more frequently such as Gamespy Arcade and Limewire.

There is only one wall/floor between the router and the computers and the computers are almost directly in line with the router (less than 5 metres distance between each computer and the router). When connected the signal strength is "excellent". There aren't any other wireless networks nearby.

I have tried changing the angles of the antennae, changing the wireless channel, and placing both network cards on constantly awake mode (as opposed to the default power saving mode). IEE 801.1x authentication is disabled. The router has the latest firmware and the network cards have the latest drivers. The network is encrypted with 128 bit WEP. Both computers are running Windows XP SP2.

Can anyone suggest anything else I could try to prevent dropouts?

Thanks in advance.

Thanks for the reply.

Are you sure that overheating is the cause?

I have been using this router for 2 years as part of a wired network (virtually identical setup but with ethernet cables instead of wireless connections) and have never had a problem with overheating even though the router was in a poorly ventilated space. The router is now in an open area with good air flow.

If you are sure it's an overheating issue, what router would you recommend?