Look in device manager under disk drives your reader(s) should appear there, click on the little box +- they should appear. If there is a yellow asterisk or question mark showing, there is an issue. There should be an option to update driver, you could give that a try. It could be several things but that is the easiest thing to check first.
I have a built-in card reader on the right side of my HP Pavilion zd8000 laptop. I placed my Micro SD card into the adapter it comes with, then place that into the card port. But, no nothing. Doesn't appear as any type of port or drive. Any tips? Maybe it's switched off by default or something? How do I get to it?