computer returned from repairs with a few annoyances

I'm not sure what's actually going on there - perhaps it would be helpful were you to provide the full path and name of the folders/files which concern you, along with their properties and attributes (Publisher, dates created/modified, original filename, version, digital signing status if any, hidden/system/archive status, read-write permissions, that sorta stuff).

That said, it would seem to me the first place to go for possible resolution of the file/folder/partition questions you present would be the shop which repaired your machine - they put 'em there, they should be able to tell you what they are and why they're there. I'd think I'd go that route before deleting or otherwise modifying anything. In chess, a good rule of thumb is to remember why a piece was placed where it was placed before you move it, pretty much the same applies to computers.

At the very least, I'd suggest backing up the current installation to removable media or external fixed drive (image the current drive, in other words), set a restore point, rename and relocate the files/folders of concern - not delete them, just rename them to something like
old.{folder/filename.extension (if any)}.old,
then gather all of them into a new folder created to park them temporarily - reboot, and see what happens; worst case, if necessary you could then choose from between a couple options to revert back to where you were before doing anything, best case, you'll find out those files/folders are just excess baggage that can be done without.

Modifying partition structure, though, is a different matter entirely, and prolly not something that should be attempted without knowing what, why, and how to go about it and being prepared adequately to cope with and remedy disaster.