INT 21,41 - Delete File
AH = 41h DS:DX = pointer to an ASCIIZ filename on return: AX = error code if CF set (see DOS ERROR CODES) - marks first byte of file directory entry with E5 to indicate the file has been deleted. The rest of the directory entry stays intact until reused. FAT pointers are returned to DOS - documented as not accepting wildcards in filename but actually does in several DOS versions