Hi Minty....You say that you get a bit flummoxed by techie talk. I'll admit that I sometimes get completely confused. I honestly thought that, because there are still a lot of Commercial organisations using Windows XP, Microsoft had extended its MSE availability to them and, all other users, for at least a further 12months.
Anyway , that apart, Avast could be a really good alternative AV programme. However, make sure that all traces of MSE are removed from your computer before installing any other AV programme........Having said that, I should realise that you have been around long enough in AB to be aware that it is unwise to have more than one AV programme, because they will conflict with each other.
Cheers......Hans.