I can send fax but not receive

On this machine you can check the menu selection to see how you have set the answer mode. There are different ways you can reviece faxes, to print right away, or store them in memory.
With these types of problems when one area does work, and the menu selections are correct, either the software is not working right especially when it is connected to the computer via USB, or the machine has a hard failiure of the modem circuit board on the fax machine.
If the machine is old and it is connected to the computer, there are software differences with the drivers, XP and Vista. Some drivers are too old for some of these faxes even if the machine still works, the drivers are outdated and the manufacture will not upgrade them.
There are other questions I have reguarding this type of problem.
Good luck.