Laptop wont start

toshiba satellite L500-1EL fail to
start. recent hardware or software change might
be the cause. i have tried to fix it using startup
repair but in Vail and used another option to
start window normally but appears black screen
with a cursor for hours. i have tried to boot it
with Window 7 operating systems, after i install
the disk and press f12, it will say press any key
to boot from Cd/dvd and once i press, it goes
back to windown loading files back to window
error recovery screen. what is the problem? how
can i fix this laptop