Tbh, don't buy premade computers if you want to get the most out of your money.
Tell your friend to cruise around the internet to learn about each component and what details he should look for when purchasing it
Also, advise him to look for parts on his current computer he can use so he can spare some money to buy less but better hardware
Plus, when he has made up his mind on what to buy, tell him to go through lots of stores to know where he can get the best prices
Oh and don't advise him that computer, he won't play games post-2003 for sure