PLS help with getting driver for modem

Hi ... I have a old dell computer >>> Dell Optiplex GX 1 P3 service Tag GABAP , chipset >> Intel 440BX PIIX4e….
I am going nuts here trying to figure out how to install the driver for the modem .... Can someone please explain what is NIC controller chip ??? Also when trying to get a modem to work is there more then one driver or whatever that needs to be downloaded or do i just need to download the right driver for my computer modem type only to get this damn thing to work ??? What I don’t understand is when I go to dell download website and try to get the driver there is option to choose from like Communication drivers or network drivers , i am confuse which one i need to download from ??? If someone could please explain whats the difference between the 2 are ??? When I boot up my computer I get pci devise needs to be install and i know that is for my modem , correct ??? I actually now have 2 modem cards here , one that came with this computer which i think its this >>> optional integrated 3Com® PCI 3C905B-TX Wakeup On LAN NIC, operating at 10 or 100 Mbps but to get the driver for this is driving me nuts ... I have when to dell site and download 3Com Controller-based v.90 Modem, v. 5.19.0.4, A04 but I am stuck here when I try to load this in the devise manager area it shows as a yellow check mark under modem …. So if someone could please explain to me how it all works would be so so much grateful… Thanks …For a windows 2000 pro version... I have gone to there website ( dell ) and i can seem to understand why when i try to open this file nothing happen or when i try to update the driver i get a yellow check mark in the devise manager area under modem ... What am i doing wrong here ??? wrong driver or wrong modem card ??? This is what i am trying to load below

Communications: 3Com Controller-based v.90 Modem, Driver, Windows 2000, English, Multi System, v. 5.19.0.4, A04
File Name a4hawk2k.exe (93 KB)
File Date 09/21/2000
File Format Hard-Drive
Modem drivers for 3Com PCI Hardware modem for Windows 2000 Professional. 46XVP and 19YRD (Hawk)

You need the driver for both your modem and your 10/100 network card that is in the machine....

Hi ... I found out what the problem is , I when back to the place where i got this computer from and asked the guy whats up with this modem here i can't seem to install the driver for it ??? He tell me its not the original modem that came with this unit .... You can imagine what i was thinking then , huh ?? So now i ask him what is the modem type and he said its a PCtel model 1688 ... So i get home and search for this driver , Well i found 2 types and i am going to be giving them a try , Hope all goes well now and i will post back if i am connected with the dell computer later on .... I would like to though thank you for assisting me here any ways ... Thanks