Sometimes, not always, upon restarting my Macbook (late-2006), the chime is repeated four more times after the initial chime. It then starts up normally.
You can take a look at the Power On Self-Test codes from Apple ( http://support.apple.com/kb/HT1547 ), copied here for convenience:
If you have 5 beeps, it might be a processor problem. Note that the chimes will be uniform, all of them the same, if there is a problem the "normal" chime is not played, just N beeps as stated above.
Does it happen in quick succession to where you could say the the unit chimes 5 times at start up? Or does the system reboot between each chime?
If they happen in quick success I would suspect a RAM Module issue. If it is so that the system reboots each time I would lean more towards an issue with the MLB's boot ROM. Late 2006 MBP parts are getting scarce since a Apple computer can only be serviced for 5 years from DOP. Hopefully that will give you a bit of information.
Another (distant) possibility is that the OS is corrupted after trying to do a software update. That one is a bit tricker to find but best tip is to run a complete backup of the unit, re-install the OS from the DVDs that shipped with the unit and the reapply all available updates (making sure the unit is attached to power the entire time).