Check that the PreSonus Inspire unit is getting power from your computer. There is a blue light on the front panel display of the unit. If it is not on, the unit is not getting power from your computer.
Test your FireWire cable with a multipurpose cable tester with a FireWire input for continuity. If your FireWire cable is shown to be faulty, replace it with a new one to see if the problem is solved.
Disconnect the audio cabling connecting your PreSonus Inspire unit to your speakers, amplifier or source controller if you are not hearing any audio or playback volume level is extremely low. Test the cabling with your cable tester, and replace any fault cabling with new, working cabling.
Make sure your PreSonus Inspire unit is getting signal from the microphone or audio device plugged into the input. There is a display on the front that will flash when the unit is getting signal from an input.
Test the XLR microphone cable or 1/4-inch Hi-Z cable plugged into the Inspire unit with your multipurpose cable tester. Replace any cabling is shown to have a faulty pin or intermittent connection with a new cable is shown to be working properly when you test it.