Hard Drive used space errors

[MetalX]

My new 80GB (actually 74.5GB) Seagate SATA hard drive is showing an incorrect reading somewhere. Right clicking on the drive in My Computer and clicking on properties, it says that 48.6GBs are used and 25.9GB are free. But when I go into the C:\ Drive (that hard drive) and when I select all the folders in C:\, it says that they only take up 37.8GB. I have selected all hidden files to be shown, and I definitely do not have an 11GB page file... does anyone know whats wrong? Is the hard drive defective or does it need defragging or something? I'm a real newb when it comes to hard drives so I'd appreciate if someone could shed some light on this for me

Thanks

 

[DelJo63]

well for one, your restore points are still hidden.
reduce the space allocated for restore points, reboot, and sleep easy --
not a significant issue here.

 

[MetalX]

Ok thanks. Seemed to help a lot, although there is still about 3 GB unaccounted for. By setting the system restore amount to 2900MB, I am still missing about 6GB (total used space is 43.8, and when I select everything in C:\, it says that everything only takes 37.9GB.