PC gaming

[mark]

Kid wants to try PC gaming but my 10 year Dell (Pentium4 2.0g, 512mb, GeForce 6200) doesn't meet the minimums requirements or barely for the games he's interested in (Teams Fortress, Starcraft/Warcraft, Total War).

As I'm basically cheap and the current system does great for my use (forums and downloading Bit-torrents) wondering if what looks like 600-700 bucks to hit the minimums for another PC enough or just wasting time/money.