I think it's the graphics chip, anyways to run pcx2 aka ps2 emulator you need at least a Geforce 6600 series and a duo core or better.
What you can try is set on speed hacks to 3 and the render is dx9 mode instead of opengl which should work a bit faster by setting it in the rendering options.
Also make sure you have the latest pcx2 build. CLICK BLUE LINK>>> SVN
Other then that can't really do much expect maybe getting a faster laptop or desktop.