I have fullscreen app using directInput. I tried to handle DEVICELOST event, so i used this code in msg pump: if((D3DDev->TestCooperativeLevel())!= D3D_OK){ if(D3DDev->TestCooperativeLevel()==D3DERR_DEVICELOST){ DIH.UnAcquire(); //dinput Sleep(500); ReleaseSurfaces();//here i release all //surfaces using POOL memory }else if(D3DDev->TestCooperativeLevel()==D3DERR_DEVICENOTRESET){ lpD3DDevice->Reset(&pp); RecoverSurfaces(); } }else{ /* here i render , update logics and so on because if im here, the device is not lost*/ } The problem is, that it never enters if(D3DDev->TestCooperativeLevel()==D3DERR_DEVICENOTRESET) so the device cannot be reseted. My app remains minimalized and i can only close it. Any ideas what can be wrong?

Ok, main problem was my stupidity after all, i placed whole code not in msg pump..
But now all is fine, but when i try to reset device, it does not return D3D_OK. What it returns i cannot say, but for sure its not one of codes mentioned in docs: D3DERR_DEVICELOST , D3DERR_DRIVERINTERNALERROR, D3DERR_INVALIDCALL,
D3DERR_OUTOFVIDEOMEMORY, E_OUTOFMEMORY.

I do release all vertex buffers and textures using D3DPOOL_DEFAULT memory before attempting to reset device. I have no idea what more should i release.. I use directSound, i have stencil shadows, i also have bumpmapped water made with two render target textures but i release them too. What else should i release?