Autosaves just after meeting informant in the first embassy mission. When I start from here, all actions - Sam and enemies -are slow and "choppy". Very frustrating to play and clearly not right.Doesnt happen if I go back to previously saved points - so I dont think the game has become corrupted. I am using a CD on a laptop, and the last few levels have been fine.

Any suggestions?

Have your resolution settings been changed for the game? Running too high of graphics settings can slow things down. Thermal vision will slow it down too on computers using onboard graphics chips like most laptops.

no all settings at lowest and unchanged. now its happening intermittently. is this a disc error? First 5 missions were no problem