Unmountable DVDs

[Phil]

Thank you for reading this.

I had encouraged an acquaintance to install Kubuntu and somehow he 
managed to wipe Windows Vista during the process. Not a major disaster 
so far but still it's an annoyance all round. The current problem for me 
is that I have to provide a solution for several rewritable DVDs that 
are now unmountable.

A batch of DVDs were formatted using K3B so that they could be reused. 
Unfortunately, they are now unmountable. I know this to be the case from 
my own past experience with K3B, no mater if "format" or "quick format" 
is selected the result is the same, a disc that is unmountable.

While delving into another laptop I've discovered that Windows 7 is able 
to mount the previously unmountable discs and format all but one of them 
as UDF discs.

Apparently buying a copy of Windows 7 or 8 is not an option. So is there 
an easy GUI for formatting or erasing discs that won't leave them 
unmountable? I've looked at "udftools" but it's use is rather complex.

-- 
Regards,
Phil