Hi newcomer and welcome to the Tom's hardware forum.
Answering to your question, yes, you need the Windows CD to install the OS again. You can tell a friend that borrow a Windows Vista x64 Home Premium and when the installation process ask you for the key, insert YOUR KEY. Is legal and you can do it without problems.
Thank you for the warm welcoming Saint!
And thank you for helping me and my problem, and now my new problem is to find a friend who has Windows Vista Home premium.