Difficult to tell. Until you mentioned the hard drive issues I was going to suggest downloading speedfan and checking how hot your processor etc. was getting. I suspect streaming video may cause consistent load/heating over a prolonged period. You can, of course, replace a hard drive, or other components such as the power supply, but if you are getting multiple failures maybe that's not the way to go. How old is the PC ? How far away from the standard spec for today ?