What are the chances of my psu frying my mb and hard drive?

Question

Computer store says it did but a friend who works on company cpu systems say he has never seen this happen.

Answer 1

yes with the correct amount of surge of power to those parts can easily damage it, since there is parts on the motherboard than control the flow, and if these get damaged with a surge it can take out lots of other pats connected to the motherboard.

Answer 2

Anything is possible but its also unlikely. If you keep your PS clean from dirt and dust along with other components you should be fine. Investing in a quality well made power supply is a must. Don't use some generic POS PS that comes with a case. They are junk.