Since the link provided by @Skunk1966 requires an account, I'll provide you a summary here:
To use sfv files, you need smartversion.
Smartversion Download Page
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Once smartversion is open, you'll find two folders on the left: the first is the location of the source file, and the second is the one you want to create.
Select the latter, then in the right part of the window, right-click on the file and choose extract.
Choose the location where you want save the iso file and press OK.
The process may take some time (depending on the power of your machine), but once finished you have your ISO.
To use sfv files, you need smartversion.
Smartversion Download Page
Code:
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Once smartversion is open, you'll find two folders on the left: the first is the location of the source file, and the second is the one you want to create.
Select the latter, then in the right part of the window, right-click on the file and choose extract.
Choose the location where you want save the iso file and press OK.
The process may take some time (depending on the power of your machine), but once finished you have your ISO.