This could very well be a hardware problem - more specifically - a failing hard drive. Is this easy to fix? No. It will require replacing your hard drive with a new one and reinstalling your operating system, applications and transferring what salvagable data you'd like to keep from the old drive (if any).
can look in bios for boot time errors stops
and disable
save reboot
mor'n likly the drive giving up
dwnld a bootable OS like knoppix or barts simple xp
then try n' boot from that
then transfer yer data to safe place