Can't get back into CDMW2 after Alt-tabbing?

[i want a laptop]

OK, So I'm playing Modern Warfare 2, lets say someone sent me an IM, I alt-tab out, read the IM, reply back, or do whatever, then I try to alt-tab back into MW2, it just sits there at a black screen. This is really annoying, I have to (basically) shut down MW2 completely, to do anything, and then reboot it all the way back up to get back to gaming. Is there a fix for this? I'm presuming it's a direct x thing, but I'm not sure, any thoughts?

Thanks