Did you let it run for a while? Usually, I leave mine on overnight just to be safe. However, whenever I find that RAM has failed, it's usually evident by flagging errors within about 5-10 minutes.
If you're RAM test passes, then we are stuck with the hard drive.
One thing, and this is a biggie depending on your setup. I once worked with a computer a few weeks ago in which I needed to clear the BIOS. What happened was the HDD reverted back to a different setting (I can't recall what it was), but I had to turn it back to IDE/SATA (maybe the setting got set to SCSI on CMOS clearing...I'm just brain farting now, I'm sorry I can't recall what this was). Anyways, because it was set wrong, as soon as windows started loading, it would pop a BSOD.