Hello..!!
Most Important of All is the Flow of Electricity Supply. The Temperature of the Space surrounding the PC needs to be maintained, though in some cases it is not essential. The Voltage being supplied to the UPS or PC needs to be monitored. If there are Power Surges and Power Fluctuations, most of the times there is a Hardware Malfunction. However at the same time many Internal Programs {Software Programs}Installed on the Computer are Corrupted, Due to which many Errors Occur.
A Precautionary measure must be taken to keep the Desktop Away from any kind of High Level Power Cables of any sort of Cables & Any sort of Electronic Devices that Carry or Use a High Frequency of Bandwidth must Always be Kept at a Safe Distance, Far Away from the Computer.
Secondary measure is Keep the CPU Dust Free. Try to make sure to Prevent any sort of Dust Particles to enter the CPU. A Thin Layered Cloth Cover is Preferable as it Prevents the Dust Particles from entering the CPU and at the same time it helps the CPU to Breath, i.e. it Allows the Air Circulation in the CPU Box.
Anyways a Good Attempt done on "Maintaining you Machine" - Article. However I feel that you missed out on both of these Important Ones.

CHEERS...!!

Till then HAPPY COMPUTING to all NETIZINES...!!