[Altair]

I am running MTU 2.315, I have downloaded MTU 2.4 but when I try to install it ...

I put in my e-mail - ok
I put in my registration number - the screen disappears and as far as I know nothing has happened.

I was told that this means the registration number is incorrect, I have cut and pasted it from my original e-mail so I know that it is correct.

I have not uninstalled the old 2.315, could this be the problem?

I worry about uninstalling it in case I cannot get it reinstalled again.