Grey screen with spinning gear

Hi all,

Have had this for a while now, when switched on i get the chime, apple logo and then goes to a blue/grey screen with the spinning gear. also at this point i get the mouse cursor which comes and goes.

Have tried all the safe mode and verbose mode.

Verbose just produces the screen shot i have attached, i left running through the night and comes up with the same message but with different time stamp

I did try and boot from my Leopard 10.5 cd but just went straight through to the grey screen.

Any help would be really appreciated