anything about the surge protector you are using. If you aren't you should be as power surges are a daily fact of life and while the power supply can deal with minor surges that capability decreases as the computer ages.
If you are using a surge protector what kind and how old is it? If it is a MOV ( Metal oxide varistor) based suppressor it likely needs replacement. MOVs have a lifetime "joule" rating. The joule is an engineering term for energy (energy can be measured in joules). The joule rating for an MOV means that when a particular MOV has received the specified amount of energy, it no longer works! This could be the result of one or two large surges or several small surges. It doesn't matter how much you paid for it when it has been hit by enough surges it is done for. Surge protectors using MOV are shunt mode suppressors as they shift the surge to ground.
Best bet for a surge protector is a series mode suppressor which affords lifetime protection as it doesn't sacrifice any components to a [power surge, instead it blocks them. They are considerably larger and MUCH heavier suppressors and also tend to be more expensive. UPS (Uninterupted Power Supplies) tend to use this type of suppression giving you that benefit plus power for a proper shutdown in event of power loss and should always be considered for computers. Their disadvantage is that the batteries usually only last two or three years before you have to replace them with new ones but it is worth it - especially when problems such as you describe never seem to happen with a good UPS.