If you are unable to locate a product or bundle on the system - it is more than likely because of the following reasons:
Product has been set to discontinued
It could be by accident or intentional, but this is the most common reason that products are no longer displayed in product or reporting screens.
Navigate to Products > Overview & tick the option to show discontinued product and click filter. (you can choose to have this option ticked by default by navigating to Settings > User Settings > Product Defaults
The product will now be displayed and you can now edit and turn off from discontinued if necessary:
Product is a bundle
Similar to the above scenario - you may be searching for a product that is a bundle without the product overview filter bar having show bundles ticked.
Carry out the step above but instead tick the option to show bundles (again you can choose to have this option ticked by default by navigating to Settings > User Settings > Product Defaults