did you READ the redhat install guide section on dual booting with MS windows ?
https://access.redhat.com/documentat...ide/index.html
the instructions will be different for
XP & vista
different for Windows7
and different for win 8 using "secureboot"
and did you REPLACE windows ??? ( what ??? xp,7,8.1 ? what)
or just the MDR that microsoft was using