|Probably can only give general suggestions:|
Does 'nothing will come on' mean no fans or LEDs in the computer and the monitor power LED doesn't come on? Try a different wall socket and bypass the surge protector.
Was the problem possibly caused by the user? Did anything happen to it or did she make any changes between the last time it worked OK and the first time it didn't?
With the power cord disconnected she can temporarily remove all unneeded cards and disconnect the drives. Then reconnect the power cord and start it up. If it gets to the logo or posting screen then one of the disconnected items must be at fault.
If everything else checks out, an abrupt failure is usually the power supply, motherboard or both.