If you trusted it when you bought it, then there are no reasons not to trust it now. You did something when cleaning the PC that caused a short, but it's difficult to determine what it was. It could be as simple as a motherboard that wasn't tight enough causing it to move slightly and short out to a post.
Thanks for your reply. I will use the PSU since it is the only one I have that will fit my case using cable management. But no over clocking on this cheap board until I get a z77.