Powerline Networking

I hooked up the Netgear XE 602 to the router modem in one office and then to the Laptop using XP in the other. Main computer is Win 98 SE. Got it to work out of the box for a day. Then it quit and hasn’t worked since. Heard that XP has many built insecurity utilities that prevent WLANs from working. Any suggestions?
Thanks,
Galen