That driver is embedded and should be supplied by Windows automatically. Since it did not, go to www.intel.com->Support and Downloads->Download Center->Top Downloads-> then click on #8 for Network Adapters. There is one driver set that works on all Intel Pro network adapters. It is called Pro2KXP. It does NOT work with VISTA. If you need a VISTA driver, look elsewhere on this Intel Site. Download the Pro2KXP driver to your computer or another computer, then be sure you know where it can be found. Then go to Start->Control Panel->System->Hardware->Device Manager-> then click on Network or Network Adapters. When given the opportunity, install the driver by telling the Device Manager the location to which you have downloaded it or placed it. It should then install automatically.
If it does not install, then the motherboard is bad. You will need to buy a PCI card network adapter... they range in price from $14 to $50. When you get ready to install a pci network card, you will need to disable or remove the current one found in the Device Manager.
In most cases the eMachine W-2623 motherboard is bad... if not yet, you have a better than 50% chance it will go bad. Depending on how old the computer is, you may be able to extend the warranty with Wal-mart, but that costs $127 and is nearly the cost of a new motherboard.
My best advice if this adapter doesn't work is to get another computer on your Christmas wish list.