Anyone buying a laptop I'd say the minimum requirements are:
4gb of RAM
an i5 processor
500gb of HDD storage.
For university, if you have no budget and are will to spend £££ I'd go for a mac book pro. Getting a virus is like super rare and that'll only happen if you download porn or something. Pcworld, curry are good places for laptops too and Dell laptops are always reliable, you can get a decent laptop with the specs I've said above for around £500, they also except student discounts.
I'm getting the new Alienware 17 which came out like 2 weeks ago. It's expensive but future proof, I play a lot of games and can't stand loading times or boot up times which is why I'm getting this machine maxed out in features.