tmp and other weird files

Tmp files have started showing up in my documents. (I’m using Windows 8.1 with Word 2013.) For example, ~WRL2403.tmp and other ~WRLs with numbers. Then there are other weird files that I also assume to be temporary files. For example, I have a grocerylist.doc that I use, but now there’s also a file named ~$ocerylist.doc.

These things would show up on my old computer (it's like getting the plague) and I would simply delete them. I started to do this again, but when I flagged them all I got a warning message that if I deleted ~WRL2403.tmp, Windows might not work right.

I did a web search on this stuff, and as best I can determine it’s okay to delete these files when you know they’re not needed. How am I supposed to know if they’re needed or not?

Well, I know that Office programs make a lot of temp files every so often in a session (it can be changed) to protect documents if something goes wrong.