Micro SDHC with a SDHC USB Adapter/Reader isn't being recognized

I just got a 16GB micro SDHC card and SDHC reader/adapter so that I could plug it into a usb port on my laptop. My computer shows the reader/adapter as “Removable Disk (H:)”, however it won’t recognize the Micro SDHC card when I put it in the adapter. If I try and open it from my computer it comes up with a message saying that I need to insert a disk. Not sure what the problem is. I have Compaq Presario CQ60 with Vista. I know there are some similar posts but I couldn’t find any solutions. Any tips/help would be greatly appreciated.