Blank screen/100% cpu usage when alt tab out of fullscreen

[Kittypretty]

Just wondering if its just me who has this issue

As it didnt appear until recently (last few updates i guess) since ive always played this way, in fullscreen but alt tab out of occasionally to use Itunes/msn/websurf)

some times it just gives me a blank screen with the regnum cursor when i switch back to RO from my desktop, and it puts a huge strain on my cpu, making it very slow and unable to do much of anything aside from ctrl alt delete to kill the process (eventually..)

now i know i can play in windowed mode..but thats just a workaround, and besides i dont like to..any clue why its doing this..and is it just me?

Using Windows 7 here anyways.