If you read the link below it notes how we find where it's at. For example SYSTEM VOLUME INFORMATION is often holding a big bag of bytes. More at:
Can someone help me free up some disc space on my hard drive?
It has used 45GB of its 60GB
Documents & Settings has used 14.2 GB
Program files used 6.84GB
Windows used 11.3GB
GPS Map folder 7.78GB
I'm running Disk Cleanup and have ticked all the boxes, but is there anything else I can do in the above folders to free up some disc space up?