If you must have XP consider some other PC that will support it.  +1 to what natakuc4 says.
I am considering buying a new Studio XPS Desktop 8300 with i7 3.4 GHz, 8 GB Ram and 2TB Serial ATA HD.  I don't want or need Windows 7 and would like to format the HD and install XP (OEM Disk) with SP3 and Media Center.  Does anybody foresee a problem with this?  Advice or horror stories would be appreciated. Thanks!
Switching From Windows 7 to XP with Media Center