Never underestimate the source of electricty for your PC. This importance was illustrated to me yet again today when my power went out & I awoke to all of my UPS's screeching at me at 4:30 in the friggin' morning... but hey, at least they went through a proper shutdown instead of getting the rug yanked from beneath their feet...

"A computer system is only as strong as its weakest feature, and many times that distinction falls on the power supply and related components. By choosing a quality power supply, surge protector, and perhaps a UPS, one can make sure that they have adequately strong and stable power to keep their system running now, as well as down the road when upgrades may increase the demand on their system."