I had the same problem as you describe on my Medion P6611 laptop (and on a previous Medion desktop that was, sadly, stolen from my apartment in early December. But I digress...) I called Medion tech support (which I have never found to be anything less than excellent), and the representative said:
The problem *may* be due to a buildup of static electricity, either on the card itself or in the card reader (I forget which it is). To fix it, do the following:
- Tturn off your computer, remove the battery and unplug the AC power adapter from the laptop if it's also attached.
- Press and hold the power button for 60 seconds or so. (This discharges the electricity from some internal component[s]--capacitors, perhaps?)
- Replace the battery, reconnect the AC adapter (if you use it) and turn on the computer.
With any luck, that should fix your problem.
P.S. One slightly related tip: When you remove a card from the card reader, just remove it. There's no need to click on "Safely remove hardware" and select the card reader's drive letter. If you do, it won't recognize cards again until you reboot or turn the machine off and back on. Different problem, but same behavior.