Hi
its either trying to assess what hardware is attached, its not seeing the HDD properly, the MBR is faulty or the boot order is being checked for a disk in the floppy drive-CD drive.
fixes are
1) make sure any USB devices that are attached at shutdown are attached at startup,
2) ghost the drive onto a new one and see if it continues (if you dont know what ghost is do a google on drive cloning)
3) Do an over the top install of your OS
4) go into the BIOS and change the boot order to boot from the HDD first.
whilst in the BIOS set it to defaults then change the settings back for things such as boot order and plug and play to yes etc.
to be honest on the times ive seen this it tends to be that the HDD is faulty and is due for replacement.