OK. I'm assuming both computers are running XP, and all you want to do is share printers and folders. I'm presuming, also, that you know the network names of each computer.
To share the internet, basically, you should just connect both computers to the router and set both to accept the IP address given to them, in the TCP/IP settings. If you've never heard of this, you can probably assume that it's set correctly.
As far as printers, go to the computer with the printer connected to it. Start->Printers and Faxes. Right-click on the printer you want to share, and hit "Sharing." Pick "share this printer," and name it whatever you'd like. Go to the other computer. Start->Printers and Faxes. Click "Add a Printer." Hit Next. Select "A network printer, or a printer attached to another computer." Hit next. Select "Browse for a Printer." Hit next, and your printer should be there on the other computer. If not, LMK and i'll help you work out an alternative. That should be it for the printer.
As far as folder sharing, simply right-click on the folder you'd like to share and hit "Sharing and Security." Select "Share this folder on the network," and name it whatever you please. I'll call my share "XXXX." Now, go to My Network Places on the other computer. Your folder should be there. If not, hit "Add a network place." Hit next, then select "Choose another network location." Type "\\thecomputersname\XXXX" without the quotes, where thecomputersname is the name of the computer with the folder you want shared, and XXXX is that folder's name. If necessary, enter the username and password for the other computer. Type a name, and you're done.
If this simply isn't working for you, there are other solutions. I do try to stay away from Windows' own networking wizard, though. I find it unnecessary.