So, finally I choosed Ivory (see my previous post), because listening carefully I think it's a little better than Garritan.
Received my package including a totally new, blistered iLok key needed for activation..... well, problem began.
I created and activated successfully my iLok account. I downloaded their client as needed, but I'm not able to install it in my computer! The installer suddenly "freezes" around 75% (sometimes around 57%) and operation does not finish successfully. Please note that my computer does not crash, only iLok installer "freezes" and I must close it using Windows Task Manager.... obviously without client installation I can't register and syncronize my iLok key, and I can't install Ivory and activate its license...... I suspect it's a very difficult problem! The problem occur with and without key plugged in USB port (so key seems not causing problem); tried to disable antivirus (nod32 3.0) but I really don't know where and what to check in my Windows.
My system is based on Intel QX9770 processor and Asus P5E64 WS Evolution motherboard, Windows XP Service Pack 3. Any possible suggestion and information is really appreciated!!! Thank you.

Ivory is used in many studios, so you will be in good company.

As to the problem contact Synthogy support who should be able to help you.
Regards

Bill

Yes I'm sure that Ivory is a very good application.
I just posted a support request on iLok's web site but no reply for the moment.... I hope to solve my problem! If not, I must activate my key in a computer of my friend, but I hope to be able to install that client on my one!
Thank you.

Solved. I received information from iLok support. I installed only client, not the drivers. It seemed drivers were not needed to prepare an iLok key (not authorizing Ivory), but it's different. Installed drivers, then installed client again, my new iLok was correctly registered and synchronized in their web site. Thank you.