Sudden, boot to XP error

i have been using bcd for a long time, and today, at the second computer start of the day, i cant get to XP, win7 is fine. error message is
"Windows could not start because of a computer disk hardware configuration problem"

i have not "messed" with any settings, and had been in XP earlier today. i did a look at disk management and see no "problems". i tried the bcd "repair" option with no success. i am at a loss here.