Just a quick tutorial for the average pc user.
When setting up your SD Card it will partition it. In short It took my 8 Gig SD card and made it 75mb in Windows. This is known but Windows can't exactly format or partition it back to 8 Gigs. Many programs can do this but you have to download them also SD cards have a protected area you don't want to damage this. If you wish to get your card back to full size again I suggest downloading this tool from the SD Association
It works on Windows and Mac
when you insert an imaged card into your machine it will show the active partition i.e. 75mb to get the full partition back just go to options and set Format - Adjustment Size to ON
Above is the default setting.
This worked great for me and I feel better about this tool because it comes from the SD Association not some freeware ad configured software that installs things you don't want.