Sorry for the delay in responding. Between work and sleep there hasn't been much free time.
One of the things about Windows 7 that takes some getting used to is how it utilizes hard drive space. There's a free tool called WinDirStat that can give you a visual idea of how your hard drive is being used.
WinDirStat - Windows Directory Statistics
You could also go through this tutorial on how to free up hard drive space with particular emphasis on options 3, 9, 11, 12, 19, 20, and 21. These usually apply to just about everyone. The other options may, or may not, apply to your computer.
Hard Disk Space - Free Up and Recover