Bremner is absolutely correct - and as a point on interest, if you open My Computer, right click on the drive - and select Properties - you will see the size listed in both ways.
Also notice that you will probably have a tad more than 80GB.
Also note that GigaBytes are GB - b means bits - which is a different thing altogether (8b = 1B). Not a problem in this post (we all know what you meant) - but it can become one if used incorrectly in other circumstances.
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