Originally posted by fantom I have a KP and as software I use GIMP for Jpeg files, and for Raw files I use Darktable I find it Excellent even if at first the interface found it difficult.There are many videos on youtube on how to use it.Both programs are free.
https://www.darktable.org/ Depending on the type of editing required, if it's RAW file processing, then Darktable, RawTherapee, maybe Lightzone or even DigiKam. There's also the very decent AfterShot (commercial).
If it's just removing red eyes, lightening this and that and the such, all of the above can do most of that, plus the Gimp, also Krita might be of interest.
And Digikam is a picture editor and catalog that's a fairly all around tool that also plays well with the others.
All of those work in most operating systems (at least Linux and Windows, maybe also MacOS for most).
And, finally, don't stay on Windows 7. It's a stale system that's barely maintained. You can't even put it online any more. Upgrade it to 10, or better, 11, or if you have something against the recent versions of Windows, just slap Linux on the machine.