My sd card reader cannot read my sd card on my home pc. The strange thing is that it recognizes my mp3 player but not my sd card. At first I thought it must be my sd card reader so I bought a new one. I tried both my old sd card and new micro sd card which I bough today but my computer does not recognize them. What's weirds is that a message popped up on my pc asking me if I wanted to format them. I formatted my new blank micro sd card. When I inserted it into my sd card reader after that, it did not show up on my pc. What could be wrong?

You check different USB ports? If not, change the USB-Port.

Many times the Front USB-Ports are a problem on an PC because of the cable which are not compatible, or say not good enough. If you used the front ports only, check the ports on the back of the comp. If that not work, you may need to invest some money to buy a good USB Hub with extrat Powersupply.

That can be a problem on a Laptop also: the power on the USB-Port isn't enough for the device!

Thanks. I tried plugging the sd card reader into the ports at the back. I plugged it into the port where the printer usually goes. Strangely enough, the printer works in that port but not the sd card reader. It is a brand new sd card reader and the small light still flashes when I plug it in. Perhaps I will try borrowing a usb hub with power supply from my colleague. If it works I will go out and buy my own one.