How I can try ESET NOD32 AntiVirus V4?

[LethalBoy]

I downloaded the trial from the official ESET site and I installed it, but I can't update it because it doesn't has any username and password for the updates??? How I can update it?

[lodore]

check your emails it should have a username and password.
the same username and password you used to access the download.

[DarrenDavisLeeSome]

You should have gotten an email from ESET that contains the trial Username and Password.

You'll need to use them both either during the installation process or afterwards in the Username and Password setup in the ESET (click on the blue/green eyeball) UI or in the Advanced Update setup in the Advanced Setup UI.