BSOD Playing Dota 2 - Unfixable Hardware Error

i was playing dota 2 for a while, mid-game, when my game froze, there was a repetitive beeping sound, often occurs to me while watching Internet videos and playing other games, but i pass it off as some bug i'll never fix. i let the beeping continue (still frozen), when i got a bsod with no stop code. it said i'd crashed due to a hardware error that was not fixable. i presume it's memory, my memory isn't particular expensive or reliable. i've never received this error before, i still get the odd page fault in non-paged area. i think my hard drive might be dying, although i don't know how to test that. in short, my suspicions are my memory or my hard drive.