After losing too much when my last machine died I bought an external hard drive and have been using the Windows Vista Backup utility every month. I looked on the drive and see that it consists of a bunch of zip files. The drive is starting to fill up, so my question: Do I need to keep the older versions of backed up information or can I just delete them and re-use the space? I suspect that if I needed to run a system restore it would look at the most recent files only, but I'm not sure. Seems that keeping a current inventory of image, music and text files plus what the most recent backup saved would do it but I need to ask the experts. Thanks.