I concur with the advice from all above.

I too build my own PC's and have even put together a duel hardrive HP laptop from e-bay repair parts (my original pro-tools machine). However over the last two years I have found it hard to beat the prices from iBuypower (disclaimer not affiliated with them or get any kickbacks! DAMN!). I selected and priced all the components and their cost for the exact same thing typically beat mines by ~$100! Go figure! So it has been a no brainer to just buy from them and they are reasonably flexible with customizing components and the OS. I have been buying the laptops for my business needs (3D CAD) and when I upgraded this year, I switched that machine to my 'music' laptop (Battalion Laptop) and retired the HP. I run the OS and protools from a SSD and the data is on a mechanical drive.