That's right. If you're using a Wired connection, just plug the network cable in. If using Wireless, just pick your network name at the initial Windows Set-up and give the system your Wireless passkey. That's all you need to do.
For the Windows 7 Dell, you can get replacement hard drives for around $50 if it's not a huge or high performance drive. If you don't have a Windows DVD / USB, you can download the official ISO from Microsoft, and use the key found on the Systen's Certificate of Authenticity sticker to re-activate Windows.