Windows XP unable to boot after SP2 installation

After I installed SP2 (XP Pro), I cannot boot my PC.
My PC consists of Gigabyte K8NXP-SLI motherboard with Athlon 64 4000+ 2.4GHz, XFX 6800GT PCI-E 256 DDR3 graphic card, 2x Hitachi 7K80 Deskstar 80GB SATA-II drives on RAID 0, with 2GB PC3200 RAM.
I’d appreciate your inputs. Thank you