http://www.hirensbootcd.net/
Next download and install the ISO Recorder version for your operating system (the operating system used to burn the cd).
Once ISO Recorder is installed, insert a blank cd then right click the Hiren'sBootCD.iso file in the Hiren's folder.
Select Copy Image to CD from the right click context menu.
Leave all settings to default in the CD Recording Wizard that opens and burn the disc.
When complete, insert the cd into your computer and restart.
You should be presented with a boot menu.
Select Start Mini Windows XP
You should now be able to copy over data to your external hard drive. I would not recommend backing up .exe files or .scr files, as there is the possibility of infection.