Windows problem

hello im budoy,

one day, when i booted my computer it suddenly restarted automatically.
at first, i dont know what to do..

but when i set up my 1st boot in BIOS to CD-ROM. and i saved it using F10 key
it restarted again.. even if i boot it using safe mode it restarts also..


What am i gonna do? Can anyone help me to solve this problem of my life.. thanks
im from philippines by the way.. :D