ssleay32.dll was removed from the mingw build of gnucash in : https://github.com/Gnucash/gnucash-on-windows/commit/7ac93fe12789a6718c3741c9419b3146bd5b0a58 But the install-fq-mods.cmd still requires it. One of those needs to change, but don't know which.
It has to be install-fq-mods.cmd. I took it out of the bundle because MinGW-W64 dropped it as (extremely) obsolete.
I've removed the ssleay check from install-fq-mods. The updated will be in tonight's nightly at https://code.gnucash.org/builds/win32/maint, please test it tomorrow. If all is well I'll make a new release bundle for the download sites.
Everything worked fine with the removal. I don't have a fresh install of Win10, but on a fresh install of the nightly, it ran as expected. Thanks!
I tested v3.5 on a clean windows 7 VM. It worked fine on a clean install, so I am going to close this bug as resolved given that it works for 2 different folks.