Having trouble with the installation.

On my C: drive, I have 130-some megabytes free.
On my D: drive, I have 3.2 megabytes free.

This game takes about 2.5 megabytes. Now, the problem I'm having is that when I change the location from the C: drive, to the D: drive (keeping the folder names), and click next, for it to continue the installation... It says that I do not have enough space on the drive for the installation.

My assumption is that it's reading the space free from the C: drive, and not the D: drive.

If there is anyway I can fix this problem, or if you can help me in whatever way, I'd appreciate it. It took me a long time to get this, because everytime I tried to download the thing, it'd only half-download, for some reason. And now I'm a bit upset at it since it's not letting me install the game itself.