New bios for asus p4p800 se

hi Tom,
I had been running xp for a few years, then my mate came around and introduced me to linux and ubuntu.
I removed ubuntu,and failed to reinstall xp, because of the file setup is different, so I abandoned the installation process, a few years have passed again of gathering dust, I would like to use this good old desktop again, I now have nothing, no onscreen prompts while booting, HDD armature pings accross and then hangs, DVD/CDROM engages but, can you help please ?
could it be the battery? could installing a replacement bios eeprom ?

thank you
Paul