Using a bad memory card reader can screw up memory cards, such as SD cards. There is little sign that there is a problem, except that Windows is hesitant to recognize it.
Windows won't fix the card, whether through formatting it, running ChkDsk, or whatever. I have found a solution involving your digital camera.
Digital cameras can format memory cards, and they seem less fussy than Windows. When a poor-quality memory card reader "wrecked" a 16GB SD card of mine, I did the following:
1. I stuck the card into my digital camera.
2. The camera complained that it was not suitable. It asked if I wanted to format it. (If the camera does not offer to format the memory card, then do so manually.)
3. After the card was formatted (with FAT32, in the case of my Samsung EX2F camera), I removed the card from the camera.
4. I plugged the memory card back into my Windows computer, and ran ChkDsk on it, asking the utility to fix all problems.
5. After ChkDsk found and corrected problems, I reformatted the SD card with NTFS for use with my computer.
The card now worked correctly.