What does Disk Management tell you about the disk(s)? See http://pcsupport.about.com/od/windows-8/a/disk-management-windows-8.htm on how to run it.
I recently bought a Lenovo ideapad flex 2-15 and on lenovo's site says that it has 500gb or 1000gb, but when I opened My Computer I have 220gb (195 in C drive and 25 gb in D drive). Why? How I can use all storage capacity if it truly has 500gb?