Scott,
Try this. Right click on the C: drive. Select Properties. This will bring up a screen with a pie chart of your C drive distribution and there will be a Cleanup button displayed to the right. Click on this button. A selection screen will come up. Make sure the box marked temporary internet files is checked. Run the program. This may work. I ran it over the weekend to clean up all of my old and not needed files. It did a good job.
Peter