Inspiron n5110 will not sleep, hibernate or shut down correctly.

For a week now my dell Inspiron 15R n5110 on windows 7 has refused to shut down sleep or hibernate.

for example, when the lid is closed this would normally put the computer to sleep and the power button would slowly blink.

Now

- the screen goes blank

- the power button stays solidly illuminated 

- and the computer cannot be woken up the only way to wake up is a hard reboot.

also when shutting down using the start button the computer goes through the motions then the screen goes blank and again the power button remains solidly illuminated. 

Strangely when a restart is selected the computer manages to shut down successfully

I have tried

- updating the display drivers and all the other drivers for that matter.

- gone into my power settings and ensured that the settings are on the defaults.

- problems persist when boot up in safe mode and  msconfig is set to just boot up the basics.

I've read through help for this problem in windows 8, but I can't translate the correct drivers to install uninstall and reinstall.

If anyone can help it would be greatly appreciated!