A few days ago my dads computer couldn't boot up and displayed the message "NTLDR missing"
We tryed to change the BIOS settings but still it didnt work
WE also tryed reinstalling windows again and that didnt work
Wierd thing happen the next day, the BIOS reset itself,
I asked my dad if he changed anything but he said he was to scared to go on.
This link has some good steps to follow to solve this problem (incidentially it could be BIOS related and might be a bad CMOS Battery. If the battery is weak it could still keep the data and time properly but other settings could be lost). If you have a multimeter you could check the battery to see if it is run down, or it is cheap to just replace it anyway).