Desperately need to un-subscribe to Entourage?

I have made a horrible mistake with the software (if it is software, I am too dumb to know) called ENTOURAGE. I had the icon in my application folder when I purchased my apple/mac/laptop..I do NOT know what I did..but somehow..I subscribed on to Entourage and, after using my private e mail in the registration process, I now am receiving all of my 3,000 old e mail messages on to ENTOURAGE. How do I de-register, disconnect, from Entourage, permanently? And, and, and, and...please read.....and, if I am successful in this endeavor...and..and..I CAN delete 1,500 messages which ENTOURAGE is holding, WILL these e mail messages also be deleted from my normal e-mail. PLEASE DO NOT ANSWER if you do not understand the full ramifications of how to help. People want to help others, that is great. But, sometimes, the answers are half baked and do not help at all. I need a professional here. thank you