An open GFCI opens both the hot & neutral connection so if that's the case almost certainly there is a GFCI upstream somewhere that needs a reset.
It's otherwise unlikely that you'd lose both hot & neutral.
To test the hot, run an incand. lamp in a pigtail socket from a known good ground to the hot connection (should be the short slot) of the dead outlets. You'll need an extension cord as a test lead and you'll need clip leads. A plug inserted and then pulled 1/8" out of the sockets/outlets/receptacles will give you a good electrical connection to the socket's interior spring loaded blades.
Be careful and wear eye protection because if you short a hot line, little globs of molten copper or aluminum will be flying through the air.
To test the neutral, run an incand. lamp in a pigtail socket from a known good hot connection of some outlet to the neutral connection (should be the long slot) of the dead outlets.
Then you'll have to find out why the GFCI tripped.