here it is: http://www.ultimatebootcd.com/download.html
(download and burn).
You could load any livecd of any light linux distro with check tools.
If it is your RAM: you should discover it quite wuick. If you have different rows of RAMs, dismount each one after the other and retest. Perhaps is 1 row dead.
If it is your HDD: start GPARTED from the livecd or from any light linux distro. And: you dont need a HDD in a PC. You can run it from USB. If your PC dont boot from USB, you could install "plop" bootloader on the HDD (on the non destructed part) and this will redirect you to your USB. Dont spend money today with HDD: the price is too high on the market.. wait for few months...;-)
And: when you are burning CDs, make all following 3 livecd:
It should help in checking the HDD later.