I need to buy a laptop but my knowledge of computer type things is truly abysmal. I need it essentially to write essays, browse the internet and download/stream things (mainly television and films).

What sort of things should I be looking out for? Ie what is a decent amount of memory, what will make a laptop run quickly/not lag behind when watching videos? I realise that I'll get at least one abusive post if this thread gets more than one reply so in advance: fuck off to those people.

Help appreciated, ta.