MacBook won't boot on Yosemite after force power off
Hard drive clicking/clunking/scraping noises (other than the usual sounds of an HDD in operation) are nearly always a bad thing and it's best to assume it's terminal.

If it is your hard disk (or if you've ever erased/replaced the disk) you won't be able to access the hardware test, in which case you will need to start your MacBook with the Applications Install disc that was supplied with your computer.