Samsung (SH-M522C/BEBN) CD-RW/DVD-ROM Combo Drive "incountered" Questions

lg dvd rom driver/combo drive i recently incountered this problem regarding this driver it seems it wont work on dvd-r cd's but it could read only cd-r or cd-audio.before it was all fine it could read

cdrom not detecting i got samsung cdrom drive.. i formated the system and i want to reinstall it.. now it showing that ntldr missing and i checked in BIOS cd rom has not detected.. can u help me ...