My husband's theory is that they aren't making money off of us so they'd like us to buy yearly licenses.

One worked with no problem but the other had issues. I wonder what the difference is? The one with no issues is 64 bit Win 7 Home and has .NET 4. So perhaps it has something to do with either or both of those.
Back in 2017, my husband's desktop had a problem (32 bit Win 7 Pro) but the other three were fine.
Anyway, I was told to contact them (it is next to impossible to find an email address) and tell them all the licenses and have them reset all of them.
Since I couldn't remember what email address or addresses I signed up with the 5 programs, I opted to use a new email address. That's the one the My Account page is now using.
I save some emails but I didn't save the email from the first time I purchased MBAM in 2008! I probably cleared it out after 7 or 8 years.