GPU change and autocad unhandled access violation reading error

Hi there,

I've recently got a new laptop, lenovo y580 and installed AutoCad 2013. I have 2 GPUs: Intel HD Graphics 4000 and nVidia GTX 660M. I have an option of assigning them to different programs. First time I've installed Acad, by default Intel HD 4000 was choosen, but as I wanted to take the avantage of better graphics, I've decided to switch to nVidia (latest drivers). And here is the problem: it was working with Intel GPU, but for some reason, once switched to nVidia, after few seconds of loading screen, it returns me the following message:

"autocad unhandled access violation reading 0x0000 exception..."

and turns off after I click ok.

Does anyone have an Idea how to tackle this one?

Cheers and regards