init panic in freebsd 7.1

[Tsu-Fan Cheng]

Hi,
    I was having a little trouble with my computer, first thought was
that the mboard was fried, but later found out it was the power supply
and replaced it. The computer started but failed to boot, here is what
it's been complaining,

exec /sbin/init error 8
exec /sbin/init.bak error 8
exec /rescue/init error8

init: not found in path /sbin/.... (a lot of paths)

panic: no init


what is that??

TFC