As this service is web-based, the first thing you should do is access the Forgot Password option and complete the given form with your details. In most of the cases this is the best and accurate approach to problems like these. If you still can't remember the information used when you first registered then contacting support is the best thing to do, because even if you don't know your credentials or any other information, you will be recognized by other means of identification if you were a member of the website. Regarding the Windows/Mac/Linux systems, there is no other tool available which can help you do this remotely.
