Ok, guys problem solved...
I eventually could locate Avast virus chest,found the file, removed it from their list of exclusion, uninstalled Zorro, downloaded a new Zorro setup exe,
turned off internet and avast, installed Zorro...
It's now up and running and even resumed the trades from last week still in green!

It's a pity that FXCM has been chosen as Zorro's broker because demos are only valid for a month, and then you start again from scratch...
OANDA would have been a better choice for longer trial.
I could open a micro live account to test it for a few months, but again I wouldn't do that with FXCM.
When is this API for OANDA or another Broker coming?
Thanks