USB missing/Driver not located.

Please bear with me as im a bit of a novice and need things explained for me!

Windows 98 - I am trying to upload my pics from dig cam to PC (which ive
done many times before) but now nothing happens. I have figured that it is
the USB and this is not present in the device manager...how do i get it
back!......In the device manager PCI Communications has a yellow triangle
with black exclamation mark...how do i fix it..have tried to follow route to
install driver but says it cant find the driver. It has been suggested to me
that i need to find the modem and reinstall but i dont know where to start to
look....do i have a disc or do i search the internet? Also have benn told to
check the BIOS..whats that?

Heres hopeful....