System restart automatically in booting process 1)Boot from cd 2)Select First Repair 3)Type map to know which drive was CD ROM drive 4)suppose cd rom drive is e then type e: press enter 5)type chkdsk /r c: and press enter after 100% compleated type exit and automatically restart the m/c in case of NTLDR Missing error same steps up to 3 rd step 4) type copy ntldr c: and press enter 5)type copy ntdectet.com c: press enter