To start, you are missing DETAILS
A link with many ideas about computer setup http://forums.adobe.com/thread/436215?tstart=0
Work through all of the steps (ideas) listed at http://ppro.wikia.com/wiki/Troubleshooting
If your problem isn't fixed after you follow all of the steps, report back with the DETAILS asked for in the questions at the end of the troubleshooting link
Along with the details, this ARTICLE might give you some tips on setting up your computer for an editing session.
Laptops have some unique issues, like normally having only one HDD, and often embedded video cards, plus "mobile" CPU's, so much will depend on your exact computer.
A decent laptop is around 10 to 20 times slower than a decent desktop and lacking in serious ways. My advise: Don't use a laptop for serious editing.