Search compatability with that OS, it should work though I'd think since 2003 is very similar to XP. Maybe if you are running server applications turn them off and see if it loads, also be sure to wait at least 5 mins, half life 2 just takes a while to load on some computers. You should be able to run it thoughm turn everything on low and try running it, if that works put graphcis up until it stops working.