No power to outlet
Are there four outlets (two in each room)that do not work?
Did these work OK until recently?
Did they all go bad at the same time?
Do you have an inventory of all circuits, to know what circuit these are on, and what else is on the same circuit? I assume you have this info and turned this circuit off when you replaced the outlet.
Possible problem: If these are the last four devices on the same circuit, the first one to get power (from the main panel) may have a loose connection.
When you replaced one of these outlets, you may not have worked on the closest one to the main panel.
Did you turn any circuit OFF before you replaced the outlet?
Before buying a house, part of the inspection process should be to test all outlets.
I'd suggest that you find a qualified electrician to investigate the problem.