I ran an application called Disk Utility X which showed me that I had a folder called private that took up 9.9 GB of my hard drive. I knew I had not put it there, and it wasn't in a libraries folder or anything, so I kinda assumed it wasa virus and deleted it. Then my whole computer stopped working, but I was able to boot in single user mode and return the files from my trash back to where they belong. The computer started working again. However, I ran disk utility x again, and noticed that the private folder now takes up 14.3 GB. The computer works again, but somehow at the cost of 5GB storage space. Any ideas why this happened?