Macbook is still running after shutdown and gets stuck in sleep mode.

[lotion]

I just installed Mountain Lion on my Macbook and everything is running smoothly apart from the computer not shutting down when I turn it off. The screen goes black, but it keeps running. The only way to turn it off completely is to hold the power button until it shuts down. Also, whenever I close it and it goes to sleep, it stays in sleep mode even after I've opened it again.
Any help would be appreciated.

 

[justperry]

Reset SMC might help.

Resetting the System Management Controller - Support - Apple

Oh, and a good way to see what is going on on shutdown is to enable Verbose Mode, do so by holding the Command-V at startup, hold until you see text on black background, this will also enable it when shut down, when it hangs write it down and post what it says.
Verbose Mode is only enabled one time by doing this, it will be normal next time when the System boots.

 

[lotion]

Thanks for the quick reply.

Resetting the SMC didn't work and all I got was a flash of text before the screen went black at shutdown.
Anyway, I ended up erasing the hard drive and installing another version of the OS. So far I haven't experienced any of the aforementioned problems.