How can I get my laptop to read micro SD card?

I have a micro SD card 4gb with external reader, and I want to add some updates but my laptop or pc will not recognize it. I didn't input orig info, it was done by a friend on their pc. When I plug into usb point on my laptop nothing happens, if I go into my computer I can see it is there, but if I double click on it, it ask for a disk to be inserted. I am not an expert on computers so I am at a loss when people start with jargon. Sorry