To troubleshoot and resolve these types of issues either you need to know about Mac repair or if you are a local you can take them to a Mac repair center who will be happy to help.
If you are unfamiliar with computer repair, we recommend that you take it to a Mac repair center as a professional should have a look at your computer then deal with it as more damage cannot be done.
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If you're not familiar with Mac computer repair, you can contact a Mac specialist to diagnose and fix the problem. Plus, Macs are known to be extremely fast and efficient, but that doesn't mean they're not prone to accidental throttling.
If for any reason you run into a problem with your Mac that you can't fix, don't be shy about taking it to a service center, making sure you find the right shop that can fix it properly. So you don't have to come back for the same problem over and over again.
When looking for a Mac specialist near you, be sure to look at the experience and knowledge of their staff. Contact them to get a feel for their knowledge of Macs, you may also want to go online for reviews and you should be able to tell a good deal from a bad one by checking the reviews.