That sound is from your Laptop Hard Drive. It's working overtime to deliver you the data.
I'd recommend you do a scan for bad sectors too-
Go to start menu, type "cmd" without the quotation marks.
Right click it and click "Run as Adminstrator"
then type "chkdsk" without the quotations. It will show any bad sectors in your HDD.
Or else do a scan following these procedures-
Right click the Start Windows icon.
In the shortcut menu, click Open Windows Explorer.
In the navigation pane, click Computer so that your drives appear in the right pane.
Right-click the drive that you want to check.
Click the Tools tab.
Click the Check now button.
In the Check Disk window, select the Automatically fix file system errors check box.
Note If you want to perform a detailed test of the hard drive, you
can select the Scan for and attempt recovery of bad sectors check box.
You should do that in the justified suspicion of existing hardware
error in any case. But please note that the operation can then take a
long time. For a first routine check, we recommend that you do not
select this option.
If the drive that you want to check is currently in use and it is your system drive, you will see a dialog box with a warning message.
In this case, click Schedule disk check.
Exit all open programs, and then restart your computer. The checking will start automatically before next Windows startup and
display the results when completed.
If you are not checking the system drive, you do not have to turn off the computer. However, the selected drive may also be in use. In
this case, you receive a message. After you have saved all files and
close all open programs, click Force a dismount.