try it this way switch of , remove the drivers and the modem, restart the computer, switch it of again then install the drivers and refit the modem.
there is a tool in win98 called HWINFO /UI
Go to start then run and write in HWINFO /UI
there is a space between the O and the forward slash / . this tool should show you the hardware , drivers , IO, IRQ , DMA system conflicts etc,
File attributes show as MAGENTA
Registry entries show as GREEN
Configuration Manager issues show as BROWN
Warnings are shown in BLUE
Error messages show in RED
mind you my memory is going i hope HWINFO still works