My suggestion for RAM testing would be to use Memtest. Download that for free, burn it onto a CD/DVD or copy onto a floppy disk if you still live in the stone age and run that. I normally allow it to do at least 4 cycles so I can compare the results / errors if any to make sure that it is failing on the same address test etc.
As for your GPU / CPU, normally manufacturers have diagnostic applications created for those specifically so maybe provide your GPU and CPU information so that if anyone else here has the same they can suggest something more suiting to your hardware .