Have you installed all the serivce pack's and windows updates & system Drivers and updated the itunes software, etc. Even checked newer Graphics, Audio and chipset driver.
There are so many reasons for the above.
Please post with the Laptop Make and Model No and I will have a look into it for you but it may take me a day or two. Currently I have a Compac R3000 with a possible failed HDD.
Private email welcome.