Goto .... File > Settings> Preferences > Audio Devices (or just hit Ctrl+P and the Audio Devices button).
Click advanced .... make sure to show all drivers (i.e. WDM, ASIO etc.) Click OK.
MME drivers are about the worst drivers but, depending on the OS you are using, might be your only choice.
If you can, select the WDM drivers for both playback and record.
If you are stuck with using MME, back under advanced, de-select the option to keep audio devices open.
In the event that all fails, back in the preferences you can click the BIG button

"revert preferences to the default settings".
After doing that you will need to go back through and set your drivers and buffers along with all other personal preferences.