Of course, you mention nothing about your processor speed, amount of RAM, make and model of the computer, amount of free space on the computer, whether you've cleaned up the junk files and defragged your computer, etc. but one common cause is the drive starts losing the ability to read data as well.
Hope this helps.
Grif
Recently when ripping CDs on my laptop, the speed has slowed down beyond exceptance. I haven't changed any setting, it just happened. Does anyone know why????

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