The word guarantee just refers to a promise that certain conditions will be fulfilled. We can use it with products, or with things that are not products:
All our products come with a 30-day money-back guarantee.
I guarantee you will enjoy the experience.
We guarantee the accuracy of the information in our reports.
A warranty is a specific type of guarantee - it is ONLY used for products, and it is a promise that if the product breaks, the seller or manufacturer will fix it or replace the product.
Fact
Anti-American demonstrators protesting in Bangladesh after the September 11, 2001 terrorist attacks carried posters of Osama bin Laden sitting alongside Bert, a beloved Sesame Street Muppet character .. More >>