Question are you trying to run Half-life 2 or just normal HL. Either way you
should make sure you have all the drivers for your hardware. www.nvidia.com
if you have Geforce Card or www.ati.com if you have a ATI card. Download any
Beta drivers they work well for me. If this doesnt work let me know
I think that to answer your question you should provide more information
about your system. I have XP running and HL2 runs great so, it is not
about XP per se but about how your computer is set up.