Sometimes Dells can be finicky, but that's not a bad thing. I think if you reinstall Windows and them immediately do the driver installs as I described you will be better off, especially if a full Windows reinstall does not scare you. (Win98 installs pretty fast.) The chipset drivers MUST go first, then video, then NIC card (if needed - Windows may do this on it's own), then audio.
Did the Soundblaster come from Dell? Look in the expansion slots and see if there is a modem card in there. It will have two RJ45 outputs on the same card that will fit a phone cord. The network card will be built into the motherboard so will NOT be in an expansion slot. The modem and the dial up networking are two different things so I think there IS a modem and it is not installed. Again, Everest can probably identify this.
If you copy and paste the full Everest report here before you start that could solve a lot of questions. Also helpful would be posting your service tag - it is a five or six digit letter/number combo on the outside of the case and/or in the BIOS screen (F2 at boot when you see the Dell logo.) That will tell us exactly what equipment that Dell was shipped with.
I would install the Netgear wireless broadband LAST, so burn what drivers you need to CD and imnstall the drivers from there. Physically remove the card until you reach this point. Install the drivers, then turn off, install the card, and reboot. Windows updates go next.
Post back with your progress.