Hi
CCLeaner destroys the Konvertor registry key under (HKEY_LOCAL_MACHINE\Software\Konvertor) and therefore the software cannot be launched anymore

Don't blame ccleaner, you should have looked at your registry entries before cleaning. Did you create a backup of the registry items as prescribed by the cleaner? if so just merge them back into the registry.

If you didn't you'll have to reinstall the program, or try a system restore.

From now on your best bet is to follow the advice laid out in my signature.

You could exclude that key from being touched by CCleaner:

"CCleaner\Options\Exclude\Add Registry". Select the Hive name in the small window, and the rest of the address in the other.

When done correctly, the "OK" button becomes active.

Welcome to the forum by the way jack.

Hello
Yes i can exclude the key by unchecking it.
I did not because the key is described as 'obsolete'.
In fact it's not