MicroSD card reader
I have been using a Kingston microSD card and reader as my primary means of flash media. Over the past few days, however, I've run into a problem: my laptop does not seem to recognize it. I plug in the reader into one of my laptop's USB ports, and it will recognize it as "removable drive G", but if I click on it, it will say "Please insert disk into drive G". Thinking it was the fault of my card or reader, I tried it on one of the school computers, and I got the "found new hardware....your hardware is ready to use...etc." message; all worked as normal. Similarly, I tried inserting only the card into my cellphone (which also uses MicroSD), and the cellphone had no issue recognizing the card.
My laptop is an Acer aspire 7520, running Vista.
Does anybody know why this might occur?