Hi Simon,
A thought for the future might be to check online whether the hardware you're about to get works well. If you do this it should stand you in good stead.
That laptop sounds ghastly, by the way - you might find that the best place to run it might be over to the nearest bin.
Failing that, I would suggest that if it's very, veeeerrrrry slow you might want to leave it booting/installing while you do something else that takes a long time.