tmp file - delete?

I was helping a friend cleanup his comp so I ck'd the "Temp" folder under "Windows" and it was full along w/ this kind of file "fffe1dc9_{C7801960-E0AF-11D9-815A-0040F48365C3}.tmp".

I also found that same kind of file in his "Windows" folder but didn't know if it was OK to delete them.

What are these files and are they OK to delete?