Suspicious Certificates

My main computer may have that Nvidia problem that keeps it from booting, so I hooked up an older pc. I added the Brave Browser. I opened it to test it and closed it almost immediately. A few seconds later, a dialog box popped up asking if I would accept the validity of certificates from a source that I could not interpret. I assumed it was from the newly installed Brave Browser, so I accepted it. Immediately a new one popped up and I accepted it. Then a third came up. Now, I was suspicious. On the next one, I clicked NO. The certificate authorizations kept coming up. I said NO to dozens, some from foreign countries, some that looked like known companies. It finally stopped when I clicked CANCEL. I don’t know where to look to get those authorizations off and I shut down until I can be sure there is no malware at play. I booted to a Windows partition to post this. Windows is a horror. I want my Tumbleweed back. How do I secure my pc?

What site are you attempting to visit that is needs the cert approved?

Proprietor NVIDA requires that you accept their terms for each NVIDIA package. So are you sure it is a cert it is asking for??

This is the confusing part. The request to approve a cert site (plural) came up AFTER I closed the browser. I have a dual monitor setup. The browser was on one monitor and, after closing the browser, these requests came up on the other monitor. I say this to show that the requests were not hidden by the open browser page that filled the screen while I was browsing.

It was definitely a cert site requesting approval. One was located in Bratislava or something similar. The last one was located in China. I canceled at that point, the dialog box disappeared, so I can’t be more specific about what it said. I just opened and closed Brave and did not see the dialog box this time.