|Setting the power selector to 220V if 110V is required will NOT fry anything. What happens in that case is all the voltages that a created would be HALF the required values. Most current PSUs no longer have a voltage selector switch but automatically sense the input voltage. |
It is possible a power supply failure can take out the motherboard and all the components plugged into the motherboard but highly unlikely.
You didn't mention changing the power supply.
If there were a power surge due to a dying power supply you may see some evidence of the damage. Burned contacts, exploded or bulged, capacitors, etc.
How about posting some system specs. Paying attention to the brand and model of the power supply.
One thing that possibly could cause a problem would be reverse polarity due to an un-grounded or improperly wired outlet. If the computer had been working OK while connected to the same outlet then that is also unlikely.