Notebook Software and How To Questions

I have had my laptop for several years now and I no longer have the box/reciept/proof of purchase. I am involved in a class action suit and my laptop is eligible for a replacement, but the claims form is asking for some sort of proof of purchase. On the site for the class action lawsuit I read this:

"Required documentation is a form of proof of purchase, which shows the date that you purchased your notebook computer. Proof of purchase can be a sales receipt, credit card or other account statement, shipping manifest, purchase order, proof of registration, or such other documentation that the Administrator deems sufficiently reliable to demonstrate that one of the specified models was purchased in the specified purchase date range, along with the product identification number found on the back of your notebook computer and the date of when the notebook computer was purchased."

I am wondering if there is any way to find out when I registered my product, because I am almost 100% sure I would have done that the moment I turned it on. Thanks for your time.