Attached Link: www.grc.com

1. This is a warning to everyone DO NOT USE WINDOWS SCANDISK!!! 2. If you want to repair / matain a Hard Drive, I highly recommend you purchase a copy of SpinRite from www.grc.com Now without actually being there to investigate, I could take a very good guess and say that it was either your Internet Explorer cache files or your swap file. By default windows Swap files Grows and Shrinks as its needed. There is a minimum depending how much RAM you have. Now if you're Internet Explorer is set to Clear the Cache after 1 day, that would explain the sudden recovery of the storage space. Just my 2 Cents.