My computer's operating system (Windows 7) crashed recently. I took out the hard drive and connected it to another computer via the disk drive. When I go to My Computer, the hard drive shows up as having 181 GB of memory used, but when I open the file, only about 4 GB of files are actually there. What caused this? Could some of the data have been corrupted? Can I just not see the files? And if so, how can I copy the data over if I can't see it? Will I be able to see it after I re install the OS?

Thank you so much for your help.