Can you boot from CD/DVD without any problems? If so, your Hardware may be fine.
I would Restore an Image of your HDD if the Hardware's fine... You do 'Backup', right?
If not, this may help you in the future once everything is working again...
Fast-Farward to 'Macrium Reflect' by clicking the Link in my YouTube Comment. Watch until 16:08 as he talks about other things from that point, which may confuse you.