jetster,
To reset the router to factory settings you first must unplug the power then look for the little hole that says reset and insert a paperclip or the like in there for a few seconds and it should reset itself back to the factory settings.
You say it is a D-link but is it wireless or wired?
how you restart it is critical as the modem must be off also on restarting the router.
remove all cables from both the router and modem except the incoming cable or phone line to the modem.
Power on router.
connect a lan cable to the modem and power turn the power source for the modem on.
insert the other end of the lan cable to the WAN port of the router. if done properly, the WAN led will light up on the router.
now connect another Lan cable from the LAN PORT #1 and then connect the other end to your networking card on your computer.
on your main computer navigate to the control panel and select internet connections and then select connections tab and then check the box to set up an internet connection and follow the wizards prompts. you should now be able to connect to the internet through your main computer.
now on the second computer..install the wireless card or the networking card and make sure it is installed properly.
if it is a wireless card the default setting should allow you to connect to the web without any configuring at all...If you can not connect to the web then there is probably something wrong with the wireless card..so check to make sure it is installed properly..There is no way except by substitution to check the card to see if it is working.
now.if your router is hard wired then connect the wires to the networking card and then to the #2 or 3 or 4 LAN PORT( it doesn't matter as to which one)
Back on the second computer navigate to the internet options and connections tab and select to set up internet connection and follow the wizard. This should allow you to get online with that computer. If not then there is probably something wrong with your networking card. Just to make sure it is not the router you can swap the connections on the router for your main computer to any of the other ports. if it comes up then check the wires to the other computer.
To set up the metwork...on the main computer navigate to control panel and select networing wizard and follow the prompts to making a floopy. Then take the floppy upstairs and insert it and allow the second computer to configure itself to the network. If there are still issues there is a great tutorial in help section of windows XP .
good luck.