HP Compaq Pro 6305 Maintenance And Service Manual page 157

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.
After inserting a media card in the reader, the computer attempts to boot from the media card.
Cause
The inserted media card has boot capability.
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.
Solution
If you do not want to boot from the media card, remove it
during boot or do not select the option to boot from the
inserted media card during the boot process.
Solving Media Card Reader Problems 149