There is a fix if it's not settings. Remember you elected not to share make/model or what settings you tried and machine settings of 2 decades of PCs mean no one could have a chance of guessing you need to go here, click that to make it work again.
This under 10 buck USB audio is typical to fix blown audio ports:
http://www.amazon.com/Syba-SD-CM-UAUD-Adapter-C-Media-Chipset/dp/B001MSS6CS
Recently I put an RCA-Y cable into my laptop from my tape dek to try to convert my cassettes into MP3s via Audacity.
Afterward neither my external speakers nor headphones work. Only sound coming thru the laptop speakers.
Any ideas as to what may have happened?

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