dual boot configuration within XP

When Linux or Mac os86 installed on the disk, where Windows has been installed before, some time it's not set dual boot by defalt. This is the fix, only using the funtion coming along with xp.

Fix:
====================
in Dos, type:
diskpart
list disk
select disk 0
list part
select part 3 // could be different depending on your partitions
active
exit
======================