So my PC (dont' worry i've got a mac as well) every now and then shuts down on it's own. I will come back and it will be on my login page, and then tells me that windows has encountered a serious error. Now i just added another gig of memory to it, but ran Memtest86 and it passed with 100%. Now i have no idea if it actually the memory, all i know is that something is wrong and is really annoying. any advice would be helpful.