If you haven't installed BI downstairs, regardless of whatever is installed upstairs: you don't have BI downstairs.

A back up really isn't anything different from a copy. So the only thing you'd need to do is right click your RTW folder, select copy, paste it somewhere else... and wait till your computer is finished.

To unzip: go to the apropiate Winzip Archive, select the installer and press extract: this will bring up a screen in which you can select a target folder (the folder where the data will be extracted to).

To get your files decompressed: right click the folder which contains all the content that needs to be decompressed, go to properties, go to the 'advanced button', and there you'll see the 'Compress contents to save disk space' box. If this has been selected, then deselect it. It's standard though to have all data uncompressed (so if you haven't been messing around to save disk space, you won't need to worry about this).