This is an advanced topic, and the description below is very quick and raw. If you have any doubts you know what you are doing, just don’t risk and don’t experiment.
After moving a FAT32 (not sure about NTFS) partition within a disk (as a whole, without looking inside, just byte-to-byte copying), Windows stops to boot. It even starts to, but later fails with the error (blue screen) - I don’t remember saying what right now (but will check).
Problem is that damn Windows keeps absolute offset of the partition data inside the boot sector of that partition!
These are 4 little-endian bytes at 1Ch offset from partition start.
Number in there should point do partition data start, that is (at least in case of extended partitions) partition offset (a sum of size of all the preceding partitions) + 63 bytes.
References: MS WIN4.1 boot record