'Could not create graphics device' Windows 7 Parallels 6

[PhlipD]

Heyy there,

I installed Parallels yesterday, installed Steam & Super Meat Boy, and was playing for many hours without a hitch.

I come back today to find this error upon opening Super Meat Boy:

Could not create graphics device.
Failed with Error: -2005530518
Format: 22
Res: 640 x 480
Windowed: 1
--------------Driver Details--------------
Driver: prl_umdd.dll
Description: Parallels Display Adapter (WDDM)
Device Name: \\.\DISPLAY1
Product: 7
Version: 14
SubVersion: 10
Build: 11800

I've tried changing launch options in Steam, reinstalling the game, reinstalling DirectX, reinstalling Parallels Tools even!

I just don't understand why it worked yesterday, but not today?!

Any ideas would be appreciated,

Cheers,
Phil D