Compaq 100eu - All-in-One PC Maintenance & Service Manual page 169

Do not know how to remove a media card correctly.
Cause
The computer's software is used to safely eject the card.
After installing the media card reader and booting to Windows, the reader and the inserted cards are not recognized
by the computer.
Cause
The operating system needs time to recognize the device if
the reader was just installed into the computer and you are
turning the PC on for the first time.
Solution
On the Windows desktop, open Computer, right-click on the
corresponding drive icon, and select Eject. Then pull the
card out of the slot.
NOTE: Never remove the card when the LED is flashing
Solution
Wait a few seconds so that the operating system can
recognize the reader and the available ports, and then
recognize whatever media is inserted in the reader.
Solving Media Card Reader Problems
159