I have had similar problems, however using Netgear DG834G, wired computer and wireless Dell laptop on a BT line.
I found that if I place the cordless phone beside the laptop it scrambles the signal. Took a few occurrences for me to make the connecetion so to speak.
I am led to believe that both use similar RF frequencies and occasionally they have an RF 'argument'.
I fixed it by turning off the Netgear, and laptop.
Then turned on the Netgear - let if configure itself - then turned on the laptop and if found the signal. The laptop is 2m from the Netgear.