Deleting .tmp files?

Does anyone know what .tmp files are which start TMPF and are stored in Local Settings and 1KB each? Also .tmp files starting with fla also stored in Local Settings and 0KB each. Can these all be deleted? Also lots of folders starting with mdf with .tmp and stored in C:\Windows\temp? They are empty folders, no hidden files in them either - looks like one for each day. Thanks.