Possible Duplicate:
Best program to visualize file system usage on Windows?
Best way to map file sizes on a PC (Windows XP)?
Possible Duplicate:
Best program to visualize file system usage on Windows?
Best way to map file sizes on a PC (Windows XP)?
Use the portable version of WinDirStat.
TreeSize Free for sure, with a simple tree based view of what is eating your space. You can even have filters. While you can choose to view by size on hard drive you can also view it by percentage (of a parent folder) and file count.