Hi
I am having the same issue on my laptop but it is happening sporadically. The laptop was purchased in 2008 so I guess its pretty old but then it was used by my parents so not subjected to the usual rough usage and wear and tear.
Could it be a HDD issue if it is coming up sporadically and not all the time ? I have re installed the OS but no respite and yes some other symptoms I am seeing are
a) Very slow boot times
b) Laptop hanging a lot and crashing
I would have expected the laptop to never start up if the HDD goes bad but in my case sometimes its starting and sometimes giving this error message.