Hardware conflict

Through Cable Broadband Hub/router and Modem, I’m using a ISA 16-bit(NIC card)that works great.I want to use a PCI 32-bit card, everytime I install it into the PCI slot, the PC and monitor comes on, but freezes. I’ll take the card out and it works again.It does the same thing when I put in a USB card.There is a shared ISA/PCI slot, should I use that one or one of the other three ? Thanks, Kenny…