I did have AVG 7.1 which has now run out, and I have twice tried to download the 7.5 edition, and just when I have spent hours waiting for it to download, and think I have done it, next time I switch on the message comes up that my 7.1 has run out and I am not protected. What am I doing wrong?
You've not mentioned actually installing the program!
You need to double-click on the file that you downloaded. (If you're not sure where it's stored on your PC, just search for 'avg75free'. The actual file name is a bit longer than that but as long as it starts with 'avg75free' it's the right file).
When the installation dialogue appears, select 'repair installation'.