To remap the Enter key on your computer, you need to use third party tools that you can access freely. You may also need to edit your computer registry, which is quite tedious. The Sharpkeys is free software that you can use to map one key to another. You can download it from http://sharpkeys.codeplex.com/.
I think it would be easier to just buy a new keyboard. You can get keyboards for most laptops in eBay for about $20. Look at YouTube for detailed instructions on how to change the keyboard. For desktops keyboards starts at $5 and can go up to $100. Why make life more complicated?