Simply download the archive (zip or 7zip) versions from here:SourceForge XAMPP File Repository
Then extract each to it's own folder in the root of any drive or partition.
For example - C:\xampp (your current version 1.7.5) | C:\xampp177 | C:\xampp173 | C:\xampp172 etc.
Get the idea?
Next run the setup_xampp.bat file found in each of the named xampp folders and your set to go.
One caveat, you can't run more than one version at once including the Control Panel, each must be Stopped and the CP exited before starting the next version.