Which free antivirus program would be best for a windows 10 laptop?
"Best" does not exist.
Each program has strengths and weaknesses, if you look at reviews.
I have done well so far with "Avast Free Antivirus".
Previously, I had "Avira Free Antivirus", too good, but the self-promotion for the paid version was eventually too pushy, also had to be completely reinstalled annually, the newer version.
In the past, I only used AVIRA. When I got a bad virus and wanted to remove it, came AVIRA, I should buy a rescue CD. I do not know if this is still the case, but instead I chose GData, a purchase program. My LG has that and has the opportunity to monitor a second PC with it for about 10, - € or so, which I use since then for free.
None at all!
Windows 10 Protects itself excellent and just use a bit of brain, then you get no fours…
https://brain.yubb.de/