backup space taken up on Mac HD (Parallels 8, Windows 7 on Mavericks)?

hi all,

i am running Parallels Desktop 8 and Windows 7 on my 2009 MBP running Mavericks. relatively recently i have noticed (i can't really remember if this was before i updated to Mavericks) that my 250 GB HD is getting filled up.

i know that 50 GB of this is dedicated to Parallels but i have move ALL my data in my documents folder over to my desktop machine and i am still seeing problems with this.

i ran WhatSize and OmniDiskSweeper and Mac Mavericks analysis are telling me that i have a 47 GB BACKUP file somewhere. it does not appear to me that i have Windows or Parallels backup options on and i am totally confused as to what may be going on. i recently installed VirtualBox and i am wondering if maybe this is the problem.

anyway, i am a relatively new mac user and a lot of this is a tad confusing for me so any help would be really welcome.

thanks in advance.