The reader must support SDHC cards. My first Windows 7 laptop didn't do SDHC! So for that machine I had to use a USB reader.
Also, it is possible the format is corrupt. Once you save what's on there, format that media.
Bob
Does anyone know why my computer is not detecting my SDHC card it use to before I installed a new drive two weeks agao, it will detect it on my old computer which is run on Windows Vista but not on the one im using now which is Windows 7 thank you

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