Yep, they should both work. If you are only running a GTX 750, it should be able to run on the computer's stock power supply. Maybe buy the GTX 750 first, and if it runs 100% on the current power supply, then you don't have to buy the new power supply.
The GTX 750 requires 20A on the 12V rail, which his stock PSU does not have. I think it only has 8A. He will need to get a new PSU, and the one he chose will even be able to run a future upgrade if he buys a more powerful card (EVGA 550b has 40A)