Stevesh is correct:
You have a Zen Cart "plugin" / "modification" installed which changes the generated URLs. We cannot tell you which one is installed based only on the URLs as there are numerous OPENSOURCE and COMMERCIAL "plugins" for Zen Cart which generate very similar URLs. What we can tell you is: One was installed and what you are reporting as an "problem" is not a problem with the module, but the module generating URLs EXACTLY as it was designed to generate them.
You stated the site was upgraded to Zen Cart 1.5.x from an older version. You stated you had someone (your kid), upgrade the site... Do you know if the site was actually "re-built from scratch (with database upgrade)" or if the site was simply "upgraded" by slapping / merging in the Zen Cart 1.5.x files (and running the database upgrade)? Do you know what "plugins" / "modifications" were installed by the person doing the upgrade (your kid)?
Plugins and Zen Cart:
Plugins in Zen Cart are essentially a collection of new files, database entries, and modifications to core Zen Cart files. There is no "plugin management" page at this time where you can go to see what "plugins" / "modifications" have been installed.
This means one needs to keep accurate, detailed, and up to date change logs (when installing, upgrading, touching any files, changing the database, etc) in order to know what "plugins" and "modifications" have been installed.
If one has not done this, one can attempt to download a "clean" copy of Zen Cart from this website and then manually compare each and every file on their website against the "clean" copy to determine what has been changed. Of course one needs to have at least a basic understanding of PHP / programming and also how to use file comparison tools...
HINT: Many of the older "plugins" for generating alternative URLs utilized additional PHP class files (in "/includes/classes").
Some advice:
It may not be a bad idea to wait for the person who upgraded your site (your kid) to be available... Or you could possibly someone willing to work for compensation (to help you with a site you generate revenue from)... Both should be able to help you determine which "plugin" / "modification" was installed in your store.
Once you know which "plugin" / "modification" is installed, then you can look into removing it (because you do not like seeing the anchors / parameters at the end of the URLs). Once removed you will see the "stock" Zen Cart URLs (with more parameters in the URLs - compared to your current site).
You can then look into installing something else (such as CEON URI Mapping) which allows you to specify URLs without anchors / parameters at the end of the URLs. Be aware, if you want the URLs to automatically generate with titles - with CEON URI Mapping, you may need to purchase an additional COMMERCIAL module.
Do not leave "backup" copies of files on the "live" website (this can cause problems and clutter the site). It would be best to first make a "copy" of the store (files and database) and then make / test changes against the copy first.
The glass is not half full. The glass is not half empty. The glass is simply too big!
Where are the Zen Cart Debug Logs? Where are the HTTP 500 / Server Error Logs?
Zen Cart related projects maintained by lhûngîl : Plugin / Module Tracker