Also, I have moved my old audacity files I created to an older laptop for temporary use. I cannot listen to the audacity files I created anymore. There is no sound. The playback devices I have in the preference of Audacity are Microsoft Sound Mapper and Speakers (High Def Audio). Neither of them work.
That’s dangerous. Did you make sure you moved both the AUP file and the associated _DATA folder to the same place or folder on the new computer? It takes both to make a show and they won’t go looking for each other.
Have you used Effect > Manage… to open the Plug-in Manager dialogue then selected and enabled the LADSPA effects you wish to use in the Audacity menus?
Are there any blue waveforms visible in these projects? If not, these projects may have included WAV files that you did not bring along from the other computer.
Otherwise, can you hear any audio on your computer in Windows Media Player? If not, go into Windows Sound and make corrections.
If the problem is only in Audacity, left-click the speaker icon by the system clock, then click “Mixer”. Play audio in Audacity then make sure in “Volume Mixer” that the Audacity slider is turned up and unmuted. Restart the computer if that does not help either.