Probably the simplest way of explaining what happens it to write it out step by step, so here goes:

1. I click shutdown or sleep in the start menu
2. Everything works fine. Programs exit etc...
3. On "Shutting down" screen, PC fans slow down, like you'd expect seconds before the thing powers off.

4. Remains like that for ~1 minute, with the circle still spinning on screen.

5. Turns off

Is there any way to see what could be causing the huge delay when shutting down? The same thing happens when going to sleep, except I just get a black screen instead of a "Shutting Down" screen.

I'm running Windows 7 Ultimate x64 with a 128GB Samsung 840 Pro SSD, i7-4770k, Asus Maximus VI Forumula mobo, R9 290X. So as you might imagine, boot times are faster than shutdown times...

Any help would be appreciated, thanks :)