Loss of wireless networking connectivity

I have established a (working) wireless network between a
Sony Vaio desktop running XP and a Sony Vaio PCG-F650
notebook with a PC Card wireless card. Both wireless
devices are NetGear, both 802.11g, and when installed,
they function beautifully. The internet connection is a
Cox cable modem, with ethernet to the desktop and an
Access Point.

The maddening problem is that within 12-24 hours of
running fine, WITH NO HUMAN INTERVENTION, the settings
seem to change and the TCP/IP connection can't be made.
When I use the Sony QuickFix utility, it checks the
networking changes, which seem to number about 18-21 in
number from the day before. The seemed to center around
power management and hibernation and I said "ah hah" but
not so fast. I turned off all the power management tools,
no screen saver, no hibernate, etc. and it still happened
again today. It is driving me crazy (and my wife wild,
since it is her computer of course.) The desktop and XP
runs like a champ and I have a continuous good wireless
signal. I suspect some Windows ME issue, but it might be
Sony too. Any ideas, or has anyone had a similar issue?
Thanks in advance, Don