Im working on my buds computer again. He has this error that says ntldr is missing. He had this problem a few months ago and we ended up getting him a new hard drive because the sectors were bad. Now all the sudden he has this error again and another possible bad drive (havent scanned it yet to find out). What could be the cause of this error to keep comming back even after installing a new drive? Works fine for a few months then bam its back.