It's entirely possible that your computer is suffering from some sort of performance degradation, perhaps due to recently installed software. This could be anything from a new operating system to device drivers to malware (unbeknowst to you).
Or it could be a problem with a physical component like a controller chip or a failing drive, even a loose cable.
You'll need to analyze this in a methodical, deliberate manner. If you are unable to do this yourself, you're better off finding someone in your area who can.
There are probably individuals here who could give you step-by-step instructions on the dozens of tests necessary to diagnose your problem, but it might take ten times longer to do it this way.
In any case, good luck, you will need it.
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