why installing xp sp1 my dual boot won't start win 2k
(dark screen say \winnt\sistem32\config\sistem missing or corrupted(about))

You have a corrupted boot sector. Re-partition format disk including MBR.

i have read that sp1 make a change in mbr sector
but i would like think MS engineers had think before how change mbr
without delete files
my fear is : cleaning hd-making same partitions-installing same OS
will produce the same mbr