When you install it, it asks what you want to associate it with, select all of the options, as they are all 'image' files.
When you have it registered open the .iso file with it, open the folder that says RAVE (disco 2 and freelander 2001<) or whatever it says, then double click Rave.exe, it asks you to extract to a folder, do that and it will extract it onto your HD so you can open it, if you want to be able to open rave without constantly opening PowerISO and extracting it, open it up in PowerISO, select the folder (rave disco 2 freelander etc.) and then click extract at the top in the software, then click the button with 3 dots on the dialogue that pops up, find program files in the box that comes up, and extract it into there. Then go into program files through my computer/windows explorer and find the rave (d2 fl etc) and open it, then find the rave.exe file and right click, select create shortcut, it will say cant be put here place on desktop instead, select yes, you will then have a direct link to RAVE from your desktop.