The best advice I can give is for you to read this review of the Best Budget Laptops under £600 by PCA. There are plenty of free programs similar to Movie Maker and DVD Maker that you can download. I would open your options to include laptops other than HP, they do not have the best reputation for reliability. You should also consider Toshiba and Asus. When you have found your ideal machine have a Google check for reviews and see what others say about it. Personally I am a Toshiba fan, but I also like Samsung and Asus.
What is ransomware and how do I protect my PC from WannaCry?