Unknown Riser Card

Hope you can understand this. I had to replace a motherboard with a new one. The old board had a riser card with expansion slots but attached to this riser card were two sets of wires connected to two jumpers on the riser card. These wires then were attached to two very small cards that went into the expansion slots on the old board. When I installed the new motherboard I used this riser card and place the very small cards in exactly the same way as the old board. Problem is computer works fine but owner can not connect to the internet. The modem is recognised in Device manager and when I run modem diagnostics everything comes up okay, but when try to connect comes up with message can not detect modem. Now I am wondering if it has anything to do with this strange riser card as the modem is attached to it. I have checked all exterior wiring for modem and okay. Do you know anything about this riser card and did I realy need to reconnect those very small cards back into the expansion slots on the board. Well hope you can understand all that. Realy appreciate your help.