go to My Computer, right click on a drive, and click properties. The capacity should be listed there. And if you right click on My Computer and go to properties, theres a lot of other info about your computer listed there

Go to my computer and put you mouse cursor over your hard drive(local disk C usually) Then it will say free space and total size. Or you can go to System tools from start, then all programs, then accessories then system tools, then disk defragmenter, then it will say the size...either or, you will find the size of your Hard drive.