System shutdown and standby

[Lee]

I have a problem with shutdown and standby. Everytime I
try to put my Computer into standby, it simply show
the 'preparing to standby' screen, then does nothing
else, stays on this screen until I have to hit the power
button on my PC. Any ideas?
Also, just recently, when I shut down my PC, it does
nothing! It will close applications, but doesnt actually
shut down, and I can still use it perfectly, again, I'm
forced to hit the power button. Anyideas to either would
be much appriciated.