Oct 2013, Ran into 'another' M$ 'feature".  
  NEW 'feature' in VISTA and beyond?

Vista & newer M$ variants have a problem with many USB SD card readers.

If a 2gig SD card is plugged into a VISTA or newer computer , with an older card reader,
it may/will only support cards up to 1gig.  You will be  asked to format the disk. Doing so you will loose capacity on the card. It will be something  like 940Mb.  (1gig) The M$ 'allowed' maximum.

The actual problem is that M$ modified the USB driver and 
held card reader manufacturers hostage by demanding $$
to get the code to burn into the hardware to make them "greater than 1gig" compatible.**
**comment posted at numerous sites by MANY.
You can try run SDFix2G to recover the disk capacity. (With your old card reader & under vista)
Then throw your old card reader away and buy a new, compatible,[M$ 'fee' paid] card reader.
Do so before you have to get pictures off the card again.

Going to reboot into vista and give it a go. 
Ok, ran SDFix2g, and at completion Vista popped up the "you need to format this disk"
message.  I closed it.  Ejected the card and put the card back into the camera, and it says it's 2gig.
I did a format with the camera "just in case".  Old SD Card reader is going in the trash.
Oh, BTW, the old card reader is greater than 1gig compatible under Ubuntu and MINT linux. FYI.

Double checking and Just had a WTF moment: 
My laptop with VISTA Home premium will read the 2gig card with the old USB card reader.
BUT the desktop with VISTA Business will not and will display the "Format" msg.
So this is not, at least, all versions on VISTA.
lots of download locations for SDFix2g in a google search.