There's a (badly presented) list of free/libre photography software at https://pixls.us/software/

A quick check of the Windows options suggests only Digikam claims video support, which uses ffmpeg so should handle everything you've got.

Thanks. I'll give it a try.

I'm not sure if I've lost some videos from my camera too. Picasa doesn't display them in the importer but copies them across with the photos. Unless, by the looks of things, if there's a folder only with videos. Which it looks like it ignores.

That would suck. :(

I always backup my files manually with system-level tools before importing to make sure I've got multiple copies, but that is an extra level of faff and takes time - makes me envy those professional photographers who have staff to do the boring shit for them.

Alas, then you'd have to manage the staff, adding a further layers of complexity, expense, speaking to people and the final ignominy, they'd have access to your photos.

I wouldn't trust anyone employed to deal with photographs not to superimpose faces of 1980s celebrities such as Mr T and Columbo* on them at every opportunity. 

*Actually, that might enhance some of the portrait pictures I've taken...

Nope, you'd hire staff to manage all the staff.

And anyone capable of superimposing faces to high enough standards would get promoted to an assistant, especially if they could do a good Mr T onto Columbo.

I usually copy the entire SD card contents to my HDD and import from there because I'm in a rush to clear the card when I want to go out and use the camera. I've had loads of folders sitting on my desktop for ages so hoping not too much has been lost.