Black screen in games after sleep mode

[weyland yutani]

I put my computer into sleep mode earlier, I woke it up latter to desktop no issue but in games I get a black screen as soon as any 3D rendering is required (I see menus etc if they're just basic menus). Any idea what the issue is? Restarting the machine cleared the issue.

I'm using a 7950 with 13.12 drivers. Windows 7 x64 has recently been reinstalled and this is the first time I've used sleep in that time. Power plan settings etc are set to high performance.

Thanks