In order to be able to download and use a translation program, you will need a Translate Net account. A free account is provided by Translate Net, but this can be rather limited, as it only includes automatic and plain English translations. If you want more advanced programs such as spell checking and the ability to create complex documents or use HTML, you'll need to pay for the right to use these features. Fortunately, that is not difficult to do and there are plenty of sites where you can get a free trial account and start to use all the features that come with paying a little extra for an upgraded account.
When you get started, you can select a free program to install on your Windows computer that you're most familiar with, such as Internet Explorer or Wordpad. Most operating systems have an internet connection facility, which means that you can load up a free website and download and use the software at no charge, even if you're on a free trial. If you've used Macs in the past, you should find that they also have a built in application that lets you download a Translate Net application onto your PC or laptop.
Once you've downloaded the program to your computer, you should open it up using a simple wizard to determine what language you're working with and set up all the features that are required for your chosen application. This is very similar to using Windows's Internet Explorer or Windows Live Messenger. Although Translate Net comes with a basic Translate application, there are other free programs that can provide the same language options as this, including the excellent Altavista program.