Check your pagefile or virtual memory file size by right clicking my computer and click properties then Advanced > Performance Settings > Advanced tab > Virtual Memory. It will probably be at a minimum of 1 gig in size.

Also, you do not mean why the total space shouls 9.7 and not 10 correct? If so its because of the caluclations dealing with 1024K and not 1000 Bytes etc. The extra 24 Bytes add up especially when you get into the larger drives.