Networking XP/Win98

While using a linksys router (WRT54G v5), my XP machine can see (and ping) my Win98 pc but cannot see XP w/Win98. I have access to internet w/ both machines, and read many instances similar to mine but I’ve exhausted my knowledge here. From what I’ve read, it sounds like a common problem. But upon swapping out the modem and between my local phone co. and IP suggesting I reset my router, I lost my network connection. Workgroup names checked, firewalls down, reinstalled NIC drivers… Any help at this point would be appreciated