debra jo, you may also want to download
SD Formater (free DL). With it you can format your SD card using windows (or as previously mentioned use your NC instead). Winimage changes the partition size of the SD card and the Windows format command will not recognize the unused partition. E.g. if you used a 4 GB card, Winimage would partition it for the .img file you used (about 128MB). SD Formater will get it back to 4GB.