|Personally I don't think this is a HD problem.|
Press Alt+Ctrl+Del to bring up Task Manager.
Click on the Applications tab and end all running programmes (don't worry about the messages threatening dire consequences)
If your noises persist click on the Processes tab then click twice on the CPU column. This will promote the processes using the most CPU time to the top of the list.
Now watch carefully to see if any process coincides with your noise.
If it does try and identify what that process belongs to, it may be glaringly obvious by it's name, or it may not...!