Messed up the installation

Hi, I have just bought the game and was installing it. When it was done, it asked for my serial number, so I looked at my e-mail, and when I came back to the setup window I couldn't find the box that came up to enter my serial. I tried clicking it and minimizing everything, but I can't find it. I think the box to enter your serial key disappeared when I checked my e-mail by clicking on chrome. The boxes on the setup are all grayed out and I can't get the serial number box to come back up.
I tried re-installing but as it was already installed it wouldn't let me overwrite the existing files. I searched my computer for the appdata folder where it is installed, but I couldn't find it so i couldn't re-install.
Any suggestions?

EDIT: I found the %appdata% folder, but I couldn't find beamng's folder within it or anything relating too it, so I have no idea if I can un-install the game, or even if anything has been installed yet.

 

I'd know how to fix this if you hadn't closed the installation.

 

I've found it and uninstalled the first one, but it still won't let me install it again, even when I choose a different place to install. Maybe it thinks I am trying to install two copies, or maybe it needs a serial key. I'll restart my computer and see what happens.

 

The way you COULD have fixed this : ALT+TAB back to the setup and it would have shown up.
The way you COULD have fixed this once it was installed : Go to %APPDATA% go up one directory then go to LOCAL\BeamNG-DRIVE-0.3\updater.exe and enter the serial.

Dunno what to do now unless we have the error message.

 

I have fixed it now-I just installed it in the folder it suggested, and it worked fine. The annoying thing is I had my serial written down, but I was unsure whether or not a 1 was a 1 or an L due to my poor writing.

Thanks for the help!