Looks like your MSI board was built specific to HP and as you say there is no support for XP .... you may have a problem. Try here:
MSI -- MICRO-STAR INT'L CO., LTD. and see if the board is recognized by the automated system ... if not maybe try the manual method and see if any of the listed board drivers with 780 chipset will install and work correctly. You may also be able to find something directly from AMD (who is the company that made the chipset itself) although I just had a quick look and no luck.