Intel Pro 2100 internet connection keeps dropping

For two month I have the Inspiron 8600 and Latitude D400 connected to a wireless network. At the beginning, after some initial setting problems worked everything smooth. But suddenly on the I8600 keeps the internet connection dropping, while the Network Connection shows excellent signal strength.

I downloaded the latest firmware Version 1.4 Release 05 for the Netgear DG824M router and the latest driver for the Intel Pro Wireless 2100 PCI Adaptor.

I unticked in wireless network connections "use windows to configure my network settings". Had to go to the Intel utility ProSet (Software version 4.1.0.0, Driver 1.2.0.56) to configure the network connection. Enabled WEP but left 802.11 Authentication open. I would prefer more security, but don’t know how to set it.

It did not help. The network connection drops randomly and doesn’t come back till I reboot the system. The latest is that the signal strength changes a lot, looses the access point totally and comes back after a few seconds. The channel setting is on 11, and the ad hoc setting is on channel 6.

The system does not pick up the signal of any other wireless network and I checked possible interference from the cordless phone.

What can I do? I can’t believe that so many have the same problem without any of the soft-hardware providers have the solution.

Inspiron 8600, Intel Pro WLAN 2100, WinXP home

Latitude D400, Truemobile 1300 WLAN, WinXP home