You can try Unlocker: UNLOCKER 1.9.1 BY CEDRICK 'NITCH' COLLOMB It's worked for me in the past.

@BK201 AND @NEEDKARMA

Thanks again for your quick response. Problem: I've changed (I know, really not clever), my computer name, so
When I try to add on my LOGON it's of course refused. It's still the same administrator's name, but a different computer name, so the trusted root certificate is being refused. It says: "to enable trust,install this certificate in the Trusted Root Certification Authorities store".
How to do that?
Thanks.

Btw Unlocker 1.9.1. couldn't solve the problem