If you plan to use different computers, you should be aware that all assignments and scores are stored in a secure remote database accessible from anywhere, therefore your grades and certificates are always up to date and visible from any computer, anywhere, anytime.
You may login using your username and password from several and different computers however some tracking parameters (bookmarks, cookies) may be stored locally on the computer where you are working so you will have to take note of where you are at in the course.