Missing Device Driver (Latitude C840)

I am missing a PCI Modem device driver after a fresh (clean) install of WinXP.  This shows up as a question mark in the Device Manager under "Other Devices."  I have downloaded and installed the following device drivers from Dell:

- 3Com Integrated LAN Driver (R49651)

- Conexant PCI Modem Driver (R47008)

- Intel Chipset Driver (R34506)

System:

- Latitude C840

None of these driver installs solved my problem.  I cannot connect to the Internet and I am assuming this missing driver is causing the problem.

I apologize in advance if I am posting in the wrong forum area or if this question has already been answered....please just point me in the right direction.  :)