Mac hangs at boot .. unmounted HDD?

hey folks

the other day i was mucking around on my macbook (10.5, 2 gigs of ram, 2.4)
and i realised that in finder/pathfinder that my one and only harddrive's
eject button was missing... i dont konw wat caused this as my mac has been
continually been on for a few days.. (using sleep instead of shutdown)
but after noticing this i tried to install a few dmgs : "no mountable file systems"

so i tried to reboot and but it just hangs on the grey screen with the initial spinning wheel... im quite new to mac so i dont konw how to boot up with the disc and do stuff like that..

but i did read on another thread to boot with ctrl S and then type in /sbin/fsck -fy
it said the hdd was ok .. i just think i need to mount it again??????

or is that just crazy talk ???

any help would be much appreciated

oh and also, when the os was working all good i did try "disk utility" , it said that the hdd was/is fine .. but when i selected it and tried to click on mount i couldnt.. it was greyed out!

Do you have more than one HDD in your MAC. If not then what are you trying mount/unmount. The default hdd on which Mac OS is installed will automatically mount during bootup and you wont be able to unmount it.

yea.. thats the thing .. that is my only hdd! and it was missing the eject button .. so i resarted .. now it just hangs on boot .......

thanks for such a quick reply!