Before I go any further, if it doesn't work, you don't need to reinstall XP. You need to press the F8 key when booting up and select Safe Mode without Networking and just uninstall, or do a system restore.
Install the Netgear driver. Do NOT use the installation utility, just browse to the driver folder and install from there. Do not reboot.
Run the small program from the link below (just in case).
h1.ripway.com/scrim_reaper/XP_FixLogon.exe
Switch off (not reboot)
Install the card
Switch on.