Drive size recognition

So i find myself in a quandry. I have a 40 GB drive that windows clearly knows the size of due to the fact that I have around 30 gb full, but under the My Computer folder, it says there is only 511 mb free and it is a 5gb drive. Yet, under computer management it recognizes the full size and gives me no problems. I want to put something on there that is bigger than 511 MB but it won't let me so I am aggravated right now, esp since Computer Management says tehre is 5.5 GB free. anyone got any help?
-Zack Peterson-

 

Is the drive partitioned?

In disk management and the bottom display of the drive (where it will list Disk 0 if you only have the one or else disk 0, disk 1, etc.) right-click and select Properties then volumes. Make sure you are showing 0 Mb for both unallocated and reserved space.

 

got it working

the stupid thing put quotas for disk space on the administrator account. Why you ask? blows my mind.