If the diagnostics pass this may be software related. Has this always happened since getting the notebook? Do you know if anything was recently installed on the system?You may wish to uninstall it to see if performance is better. You can run system restore and load a save point dated just prior to you started receiving the error. If you aren't familiar with system restore the following like will give more details on it. It also details how to run a PC restore or a manual reinstall if all else fails and the poor performance doesn’t get any better.