Hi there, Roxanne. Sometimes, cache-related issues can cause your QuickBooks to load incorrectly. I recommend going through some basic browser troubleshooting steps to resolve in adding a new inventory item.
Let’s start by accessing QuickBooks in incognito mode or a private window by clicking the three dots icon at the side of your browser.

If this works, you can clear your browser's cache and cookies and any temporary files running in your browser that may have caused the malfunctions. Otherwise, you can use other supported browsers to ensure QBO runs efficiently.
In case you want to delete a product in your account, you can make them inactive and reactivate it anytime.
If the problem continues, please let us know, and we can explore further solutions together.