ATI will not install

Desktop PC running windows 8.1 (64 bit)
Currently drives
C drive = 60GB SSD about 1GB free
D drive = 2 TB HDD about 1.24 GB free

I have just purchased a new 250GB SSD from Crucial and an ATI licence. before proceeding with the changing of the SSDs I contacted Crucial to ask these 2 questions.
1 - Does it matter which drive I choose to install ATI.
2 - Would 1GB be enough free space to install and run ATI, if I chose to put it on the smaller SSD.

They answered that 1GB would be enough and that it doesn't matter where it is installed to.

So I registered my copy with Acronis and received my 64 digit code.
I then went to the address given to me by Crucial and downloaded ATI, I started the install and chose to install it to C drive, but after about 20secs of the "Installing ATI" window I got the error message saying "There is not enough space to install etc."
I thought never mind I'll just install it on D drive, but again I got the same error "Not enough space etc." but this drive has over 1TB of free space.

So, can anyone PLEASE tell me why this is happening,
I have a laptop running Windows 7 and it has been suggested that I install ATI to it (This has been done successfully) take the SSD from the desktop, copy it to a spare ext HDD I have, then re copy it to the new SSD, then fit it back into the desktop.
WILL this work, and do I do a backup or clone each time.

sorry this is a very long post, but I wanted you to have as much info as possible.
Thanks to any replies
Dave